The Roman emperor was the ruler of the
Roman Empire
The Roman Empire ( la, Imperium Rōmānum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican
Republican can refer to:
Political ideology
* An advocate of a republic, a type of governme ...

during the
imperial
Imperial is that which relates to an empire, emperor, or imperialism.
Imperial or The Imperial may also refer to:
Places
United States
* Imperial, California
* Imperial, Missouri
* Imperial, Nebraska
* Imperial, Pennsylvania
* Imperial, Texas
* ...
period (starting in 27 BC). The emperors used a variety of different titles throughout history. Often when a given Roman is described as becoming "emperor" in English, it reflects his taking of the title ''
Augustus
Caesar Augustus (23 September 63 BC19 August AD 14) was the first Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles through ...
'' or ''
Caesar
Gaius Julius Caesar (; 12 July 100 BC – 15 March 44 BC) was a Roman people, Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey Caesar's C ...
''. Another title often used was ''
imperator
The Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with" ...

'', originally a military honorific. Early emperors also used the title ''
Princeps
Princeps (plural: principes) is a Latin word meaning "first in time or order; the first, foremost, chief, the most eminent, distinguished, or noble; the first man, first person". As a title, "princeps" originated in the Roman Republic wherein the ...
Civitatis'' ('first citizen'). Emperors frequently amassed
republican
Republican can refer to:
Political ideology
* An advocate of a republic, a type of government that is not a monarchy or dictatorship, and is usually associated with the rule of law.
** Republicanism, the ideology in support of republics or against ...
titles, notably ''
princeps senatus
The ''princeps senatus'' (plural ''principes senatus'') was the first member by precedence of the Roman Senate. Although officially out of the ''cursus honorum
The ''cursus honorum'' (; , or more colloquially 'ladder of offices') was the sequ ...
'', ''
consul
Consul (abbrev. ''cos.''; Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman ...
,'' and ''
pontifex maximus
The (Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation w ...
''.
The legitimacy of an emperor's rule depended on his control of the
army
An army (from Latin ''arma'' "arms, weapons" via Old French ''armée'', "armed" eminine, ground force or land force is a fighting force that fights primarily on land. In the broadest sense, it is the land-based military branch, service branc ...

and recognition by the
Senate
The Curia Julia in the Roman Forum ">Roman_Forum.html" ;"title="Curia Julia in the Roman Forum">Curia Julia in the Roman Forum
A senate is a deliberative assembly, often the upper house or Debating chamber, chamber of a bicameral legislatu ...

; an emperor would normally be proclaimed by his troops, or invested with imperial titles by the Senate, or both. The first emperors reigned alone; later emperors would sometimes rule with co-emperors and divide administration of the empire between them.
The Romans considered the office of emperor to be distinct from that of a king. The first emperor,
Augustus
Caesar Augustus (23 September 63 BC19 August AD 14) was the first Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles through ...

, resolutely refused recognition as a monarch. For the first three hundred years of Roman emperors, from Augustus until
Diocletian
Diocletian (; la, Gaius Aurelius Valerius Diocletianus; born Diocles; 22 December c. 244 – 3 December 311) was from 284 to 305. Born to a family of low status in , Diocletian rose through the ranks of the military to become a commander of ...
, efforts were made to portray the emperors as leaders of the republic, fearing any association with the kings of Rome prior to the Republic.
From Diocletian, whose
tetrarchic reforms also divided the position into one emperor in the
West
250px, A compass rose with west highlighted in black
West or Occident is one of the four cardinal directions or points of the compass
The points of the compass are the vectors by which planet-based directions are conventionally defined. A co ...

and one in the
, until the end of the Empire, emperors ruled in an openly monarchic style and did not preserve the nominal principle of a republic, but the contrast with "kings" was maintained: although the imperial succession was generally hereditary, it was only hereditary if there was a suitable candidate acceptable to the army and the bureaucracy, so the principle of automatic inheritance was not adopted. Elements of the republican institutional framework (senate, consuls, and magistrates) were preserved even after the end of the Western Empire.
The reign of
Constantine the Great
Constantine I ( la, Flavius Valerius Constantinus; ; 27 February 22 May 337), also known as Constantine the Great, was Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). Th ...

witnessed the removal of the
Caput Mundi from
Rome
, established_title = Founded
, established_date = 753 BC
, founder = King Romulus
, image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg
, map_caption = The te ...

to
Constantinople
la, Constantinopolis ota, قسطنطينيه
, alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse
Old Norse, Old Nordic, or Old Scandinavian is a stage of development of North Germa ...

, formerly known as Byzantium, in 330 AD. The Western Roman Empire collapsed in the late 5th century after multiple invasions of imperial territory by
Germanic
Germanic may refer to:
* Germanic peoples, an ethno-linguistic group identified by their use of the Germanic languages
** List of ancient Germanic peoples and tribes
* Germanic languages
:* Proto-Germanic language, a reconstructed proto-language of ...

barbarian
A barbarian is a human
Humans (''Homo sapiens'') are the most abundant and widespread species
In biology
Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Bioc ...

tribe
The term tribe is used in many different contexts to refer to a category of human social group. The predominant usage of the term is in the discipline of anthropology. The definition is contested, in part due to conflicting theoretical understa ...

s.
Romulus Augustulus
Romulus Augustus ( 465 – after 511?), nicknamed Augustulus, was Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles throughout ...
is often considered to have been the last emperor of the West, until his forced abdication in 476, although
Julius Nepos
Julius Nepos ( 430 – 480 AD) was ''de jure'' and ''de facto'' Roman emperor of the Western Roman Empire, West from 474 to 475 and then only ''de jure'' until his death in 480. Born to a distinguished family, he succeeded his uncle, Marcellinus ( ...

maintained a claim recognized by the Eastern Empire to the title until his death in 480. Following Nepos' death, the Eastern emperor
Zeno
Zeno or Zenon ( grc, Ζήνων) may refer to:
People
* Zeno (name), including a list of people and characters with the name
Philosophers
* Zeno of Elea (), philosopher, follower of Parmenides, known for his paradoxes
* Zeno of Citium (333 – 2 ...
abolished the division of the position and proclaimed himself as the sole emperor of a reunited Roman Empire. The subsequent Eastern emperors ruling from
Constantinople
la, Constantinopolis ota, قسطنطينيه
, alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse
Old Norse, Old Nordic, or Old Scandinavian is a stage of development of North Germa ...

continued to style themselves "Emperor of the Romans" (later βασιλεύς Ῥωμαίων in Greek), but are often referred to in modern scholarship as
Byzantine emperors.
Constantine XI Palaiologos
Constantine XI Dragases Palaiologos or Dragaš Palaeologus ( el, Κωνσταντῖνος Δραγάσης Παλαιολόγος, ''Kōnstantînos Dragásēs Palaiológos''; 8 February 1405 – 29 May 1453) was the last List of Byzantine emp ...
was the last Roman emperor in Constantinople, dying during the
Fall of Constantinople
The fall of Constantinople ( grc-x-byzant, Ἅλωσις τῆς Κωνσταντινουπόλεως , translit=Hálōsis tē̂s Kōnstantīnoupóleōs ; tr, İstanbul'un Fethi, lit=Conquest of Istanbul ) was the capture of the capital
Cap ...
to the
Ottoman Empire
The Ottoman Empire (; ', ; or '; )info page on bookat Martin Luther University) // CITED: p. 36 (PDF p. 38/338). was an empire that controlled much of Southeastern Europe, Western Asia, and North Africa, Northern Africa between the 14th ...
in 1453.
The
"Byzantine" emperors from
Heraclius
Heraclius ( el, Ἡράκλειος, ''Hērakleios''; c. 575 – 11 February 641), sometimes called Heraclius I, was the Byzantine emperor
This is a list of the Byzantine emperors from the foundation of Constantinople
la, Constantinop ...
in 629 and onwards adopted the title of ''
basileus
''Basileus'' ( el, βασιλεύς) is a Greek term and title
A title is one or more words used before or after a person's name, in certain contexts. It may signify either generation, an official position, or a professional or academic quali ...
'' (), which had originally meant ''king'' in Greek but became a title reserved solely for the Roman emperor and the ruler of the
Sasanian Empire
The Sasanian () or Sassanid Empire, officially known as the Empire of Iranians (, ''Iran (word), Ērānshahr''), and also called the Neo-Persian Empire by historians, was the last Persian Empire, Persian imperial dynasty before the spread of I ...

. Other kings were then referred to as ''rēgas''.
In addition to their
pontifical
The Roman Pontifical, in Latin th is the Roman Catholic liturgical book which contains the rites and ceremonies usually performed by bishop
A bishop is an ordained, consecrated, or appointed member of the Clergy#Christianity, Christian clergy ...
office, some emperors were given divine status after death. With the eventual hegemony of Christianity, the emperor came to be seen as
God's chosen ruler, as well as a
special protector and leader of the Christian Church on Earth, although in practice an emperor's authority on Church matters was subject to challenge.
Due to the cultural rupture of the Turkish conquest, most western historians treat Constantine XI as the last meaningful claimant to the title Roman emperor. From 1453, one of the titles used by the
Ottoman Sultans
The sultans of the Ottoman Empire ( tr, Osmanlı padişahları), who were all members of the Ottoman dynasty (House of Osman), ruled over the transcontinental empire from its perceived inception in 1299 to Dissolution of the Ottoman Empire, it ...
was "Caesar of Rome" (Turkish: ''Kayser-i Rum''), part of their titles until the Ottoman Empire ended in 1922. A Byzantine group of claimant Roman emperors existed in the
Empire of Trebizond
The Empire of Trebizond, or Trapezuntine Empire, was a monarchy
A monarchy is a form of government in which a person, the monarch
A monarch is a head of stateWebster's II New College DictionarMonarch Houghton Mifflin. Boston. 2001 ...
until its conquest by the Ottomans in 1461, though they had used a modified title since 1282.
Eastern emperors in Constantinople had been recognized and accepted as Roman emperors both in the East, which they ruled, and by the
papacy
The pope ( la, papa, from el, πάππας, translit=pappas, "father"), also known as the supreme pontiff () or the Roman pontiff (), is the bishop of Diocese of Rome, Rome, chief pastor of the worldwide Catholic Church, and head of state o ...
and
Germanic kingdoms of the West until the deposition of
Constantine VI
Constantine VI ( gr, Κωνσταντῖνος, ''Kōnstantinos''; 14 January 771 – before 805Cutler & Hollingsworth (1991), pp. 501–502) was Byzantine emperor from 780 to 797. The only child of Emperor Leo IV the Khazar, Leo IV, Constantine ...

and accession of
Irene of Athens
Irene of Athens ( el, Εἰρήνη, ; 752 – 9 August 803), surname Sarantapechaina (), was Byzantine empress consort
The Byzantine Empire, also referred to as the Eastern Roman Empire, or Byzantium, was the continuation of the Roman E ...

as
Empress regnant
A queen regnant (plural: queens regnant) is a female monarch
A monarch is a head of stateWebster's II New College DictionarMonarch Houghton Mifflin. Boston. 2001. p. 707. Life tenure, for life or until abdication, and therefore the head of st ...
in 797. Objecting to a woman ruling the Roman Empire in her own right and issues with the eastern clergy, the Papacy would then create a rival lineage of Roman emperors in western Europe, the
Holy Roman Emperor
The Holy Roman Emperor, originally and officially the Emperor of the Romans ( la, Imperator
The Latin word "imperator" derives from the stem of the verb la, imperare, label=none, meaning 'to order, to command'. It was originally employed as ...
s, which ruled the
Holy Roman Empire
The Holy Roman Empire ( la, Sacrum Romanum Imperium; german: Heiliges Römisches Reich) was a multi-ethnic complex of territories in Western
Western may refer to:
Places
*Western, Nebraska, a village in the US
*Western, New York, a town i ...
for most of the period between 800 and 1806. These emperors were never recognized as Roman emperors by the court in Constantinople and their coronations resulted in the medieval
problem of two emperors
The problem of two emperors or two-emperors-problem (deriving from the German language, German term ''Zweikaiserproblem'')The term was introduced in the first major treatise on the issue, by W. Ohnsorge, cf. . is the historiographical term for the ...
.
Background and beginning

Modern historians conventionally regard
Augustus
Caesar Augustus (23 September 63 BC19 August AD 14) was the first Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles through ...

as the first Emperor whereas
Julius Caesar
Gaius Julius Caesar (; 12 July 100 BC – 15 March 44 BC) was a Roman
Roman or Romans most often refers to:
*, the capital city of Italy
*, Roman civilization from 8th century BC to 5th century AD
*, the people of ancient Rome
*', shortened ...

is considered the last
dictator
A dictator is a political leader who possesses absolute power. A dictatorship
A dictatorship is a form of government
A government is the system or group of people governing an organized community, generally a state.
In the c ...
of the
Roman Republic
The Roman Republic ( la, Rēs pūblica Rōmāna ) was a state of the classical Roman civilization, run through public
In public relations
Public relations (PR) is the practice of managing and disseminating information from an indiv ...
, a view having its origins in the Roman writers
Plutarch
Plutarch (; grc-gre, Πλούταρχος, ''Ploútarchos''; ; AD 46 – after AD 119) was a Greek Middle Platonist
Middle Platonism is the modern name given to a stage in the development of Platonic philosophy, lasting from about 90 BC&nbs ...

,
Tacitus
Publius Cornelius Tacitus ( , ; – ) was a Roman historian and politician. Tacitus is widely regarded as one of the greatest Roman historians by modern scholars.
He lived in what has been called the Silver Age of Latin literature
Classi ...

and
Cassius Dio
Lucius Cassius Dio (; ) or Dio Cassius ( ''Dion Kassios'')), Cassius Lucius Dio or Cassius Claudius Dio; alleged to have the ' (nickname) Cocceianus was a Roman statesman and historian of Greek and Roman origin. He published 80 volumes of the ...
. However, the majority of Roman writers, including
Josephus
Flavius Josephus (; grc-gre, Ἰώσηπος, ; 37 – 100) was a first-century and military leader, best known for ', who was born in —then part of —to a father of descent and a mother who claimed royal ancestry.
He initially fought a ...

,
Pliny the Younger
Gaius Plinius Caecilius Secundus, born Gaius Caecilius or Gaius Caecilius Cilo (61 – c. 113), better known as Pliny the Younger (), was a lawyer, author, and magistrate of Ancient Rome
In historiography, ancient Rome is Roman people, Rom ...

,
Suetonius
Gaius Suetonius Tranquillus (), commonly known as Suetonius ( ; c. AD 69 – after AD 122), was a Roman historianRoman historiography stretches back to at least the 3rd century BC and was indebted to earlier Greek historiography. The Romans ...

and
Appian
Appian of Alexandria (; grc-gre, Ἀππιανὸς Ἀλεξανδρεύς ''Appianòs Alexandreús''; la, Appianus Alexandrinus; ) was a historian with citizenship who flourished during the reigns of , , and .
He was born c. 95 in . Afte ...
, as well as most of the ordinary people of the Empire, thought of Julius Caesar as the first Emperor.
At the end of the Roman Republic no new, and certainly no single, title indicated the individual who held supreme power. Insofar as ''emperor'' could be seen as the English translation of
imperator
The Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with" ...

, then Julius Caesar had been an emperor, like several Roman
generals
A general officer is an officer
An officer is a person who has a position of authority
In the fields of sociology
Sociology is the study of society, human social behaviour, patterns of social relationships, social interaction, and cult ...
before him. Instead, by the end of the
civil wars
A civil war, also known as an intrastate war in polemology, is a war
War is an intense armed conflict between states
State may refer to:
Arts, entertainment, and media Literature
* ''State Magazine'', a monthly magazine publish ...
in which Julius Caesar had led his armies, it became clear that there was certainly no consensus to return to the
old-style monarchy, but that the period when several officials, bestowed with equal power by the senate, would fight one another had come to an end.
Julius Caesar, and then Augustus after him, accumulated offices and titles of the highest importance in the Republic, making the power attached to those offices permanent, and preventing anyone with similar aspirations from accumulating or maintaining power for themselves. However, Julius Caesar, unlike those after him, did so without the Senate's vote and approval.
Julius Caesar held the Republican offices of
consul
Consul (abbrev. ''cos.''; Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman ...
four times and
dictator
A dictator is a political leader who possesses absolute power. A dictatorship
A dictatorship is a form of government
A government is the system or group of people governing an organized community, generally a state.
In the c ...
five times, was appointed dictator in perpetuity (''
dictator perpetuo
''Dictator perpetuo'' (English: "dictator in perpetuity"), also called ''dictator in perpetuum'', was the office held by Julius Caesar
Gaius Julius Caesar (; 12 July 100 BC – 15 March 44 BC) was a Roman people, Roman general and statesman who ...
'') in 45 BC and had been "pontifex maximus" for a long period. He gained these positions by senatorial consent and just prior to his assassination,
was the most powerful man in the Roman world.

In his will, Caesar appointed his adopted son Octavian as his heir. On Caesar's death, Octavian inherited his adoptive father's property and lineage, the loyalty of most of his allies and – again through a formal process of senatorial consent – an increasing number of the titles and offices that had accrued to Caesar. A decade after Caesar's death,
Octavian's victory over his erstwhile ally
Mark Antony
Marcus Antonius (14 January 1 August 30 BC), commonly known in English as Mark Antony, was a Ancient Rome, Roman politician and general who played a critical role in the Crisis of the Roman Republic, transformation of the Roman Republic f ...
at
Actium
Actium or Aktion ( grc, Ἄκτιον) was a town on a promontory in ancient Acarnania at the entrance of the Ambraciot Gulf off which Octavian
Caesar Augustus (23 September 63 BC19 August AD 14) was the first Roman emperor, reigning from ...

put an end to any effective opposition and confirmed Octavian's supremacy.
In 27 BC, Octavian appeared before the Senate and offered to retire from active politics and government; the Senate not only requested he remain, but increased his powers and made them lifelong, awarding him the title of ''
Augustus
Caesar Augustus (23 September 63 BC19 August AD 14) was the first Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles through ...
'' (the elevated or divine one, somewhat less than a god but approaching divinity). Augustus stayed in office until his death; the sheer breadth of his superior powers as ''princeps'' and permanent ''imperator'' of Rome's armies guaranteed the peaceful continuation of what nominally remained a republic. His "restoration" of powers to the Senate and the people of Rome was a demonstration of his ''
auctoritas
300px, Representation of a sitting of the Roman Senate: Cicero attacks Catilina, Catiline, from a 19th-century fresco
''Auctoritas'' is a Latin word which is the origin of English "authority". While historically its use in English was restricted ...
'' and pious respect for tradition.
Some later historians such as Tacitus would say that even at Augustus' death, the true restoration of the Republic might have been possible. Instead, Augustus actively prepared his adopted son
Tiberius
Tiberius Caesar Augustus (; 16 November 42 BC – 16 March AD 37) was the second Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titl ...

to be his successor and pleaded his case to the Senate for inheritance on merit. The Senate disputed the issue but eventually confirmed Tiberius as ''princeps''. Once in power, Tiberius took considerable pains to observe the forms and day-to-day substance of republican government.
Classical period
Rome had no single constitutional office, title or rank exactly equivalent to the English title "Roman emperor". Romans of the Imperial era used several titles to denote their emperors, and all were associated with the pre-Imperial, Republican era.
The legal authority of the emperor derived from an extraordinary concentration of individual powers and offices that were extant in the Republic rather than from a new political office; emperors were regularly elected to the offices of
consul
Consul (abbrev. ''cos.''; Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman ...
and
censor
Censor may refer to:
People with the name
*Cato the Elder
Marcus Porcius Cato (; 234–149 BC), also known as Cato the Censor ( la, Censorius), the Elder and the Wise, was a Roman soldier, senator
The Curia Julia in the Roman Forum ">R ...
. Among their permanent privileges were the traditional Republican title of ''
princeps senatus
The ''princeps senatus'' (plural ''principes senatus'') was the first member by precedence of the Roman Senate. Although officially out of the ''cursus honorum
The ''cursus honorum'' (; , or more colloquially 'ladder of offices') was the sequ ...
'' (leader of the Senate) and the religious office of ''
pontifex maximus
The (Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation w ...
'' (chief priest of the
College of Pontiffs
The College of Pontiffs ( la, Collegium Pontificum; see ''collegium
A (plural ), or college, was any association in ancient Rome with a legal personality. Such associations could be civil or religious.
The word literally means "society", f ...
). Every emperor held the latter office and title until
Gratian
Gratian (; la, Flavius Gratianus; 18 April 359 – 25 August 383) was Roman emperor, emperor of the Western Roman Empire, western part of the Roman Empire from 367 to 383. The eldest son of Valentinian I, Gratian accompanied his father on severa ...

surrendered it in AD 382 to
Pope Siricius
Pope Siricius (334 – 26 November 399) was the bishop of Rome
A bishop is an ordained, consecrated, or appointed member of the Clergy#Christianity, Christian clergy who is generally entrusted with a position of authority and oversight.
Within ...

; it eventually became an auxiliary honor of the
Bishop of Rome
A bishop is an ordained, consecrated, or appointed member of the Clergy#Christianity, Christian clergy who is generally entrusted with a position of authority and oversight.
Within the Catholic, Eastern Orthodox, Oriental Orthodox, Moravian Chu ...

.
These titles and offices conferred great personal prestige (''
dignitas'') but the basis of an emperor's powers derived from his ''
auctoritas
300px, Representation of a sitting of the Roman Senate: Cicero attacks Catilina, Catiline, from a 19th-century fresco
''Auctoritas'' is a Latin word which is the origin of English "authority". While historically its use in English was restricted ...
'': this assumed his greater powers of command (''
'') and tribunician power (''
'') as personal qualities, separate from his public office. As a result, he formally outranked provincial governors and ordinary magistrates. He had the right to enact or revoke sentences of capital punishment, was owed the obedience of private citizens (''privati'') and by the terms of the ''ius auxiliandi'' could save any
plebeian
In ancient Rome, the plebeians (also called plebs) were the general body of free Roman citizenship, Roman citizens who were not Patrician (ancient Rome), patricians, as determined by the capite censi, census, or in other words "commoners". Both ...
from any
patrician
Patrician may refer to:
* Patrician (ancient Rome), the original aristocratic families of ancient Rome, and a synonym for "aristocratic" in modern English usage
* Patrician (post-Roman Europe), the governing elites of cities in parts of medieval a ...
magistrate's decision. He could
veto
A veto (Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Re ...
any act or proposal of any magistrate, including the
tribunes of the people
Tribune of the plebs, tribune of the people or plebeian tribune ( la, tribunus plebis) was the first office of the Roman Republic, Roman state that was open to the plebs, plebeians, and was, throughout the history of the Republic, the most important ...

(''ius intercedendi'' or ''ius intercessionis''). His person was held to be sacred.
Roman magistrates on official business were expected to wear the form of
toga
The toga (, ), a distinctive garment of ancient Rome, was a roughly semicircular cloth, between in length, draped over the shoulders and around the body. It was usually woven from white wool, and was worn over a tunic. In Roman historical tr ...
associated with their office; different togas were worn by different ranks; senior magistrates had the right to togas bordered with purple. A triumphal ''imperator'' of the Republic had the right to wear the ''toga picta'' (of solid purple, richly embroidered) for the duration of the triumphal rite. During the Late Republic, the most powerful had this right extended. Pompey and Caesar are both thought to have worn the triumphal toga and other triumphal dress at public functions. Later emperors were distinguished by wearing ''
toga
The toga (, ), a distinctive garment of ancient Rome, was a roughly semicircular cloth, between in length, draped over the shoulders and around the body. It was usually woven from white wool, and was worn over a tunic. In Roman historical tr ...
e purpurae'', purple togas; hence the phrase "to don the purple" for the assumption of imperial dignity.
The titles customarily associated with the imperial dignity are ''
imperator
The Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with" ...

'' ("commander"), which emphasizes the emperor's military supremacy and is the source of the English word ''emperor''; ''
Caesar
Gaius Julius Caesar (; 12 July 100 BC – 15 March 44 BC) was a Roman people, Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey Caesar's C ...
'', which was originally a name but came to be used for the designated heir (as ''Nobilissimus Caesar'', "Most Noble Caesar") and was retained upon accession. The ruling emperor's title was the descriptive ''Augustus'' ("majestic" or "venerable", which had tinges of the divine), which was adopted upon accession. In Greek, these three titles were rendered as ''
autokratōr'' (""), ''kaisar'' (""), and ''augoustos'' ("") or ''sebastos'' ("") respectively. In
Diocletian
Diocletian (; la, Gaius Aurelius Valerius Diocletianus; born Diocles; 22 December c. 244 – 3 December 311) was from 284 to 305. Born to a family of low status in , Diocletian rose through the ranks of the military to become a commander of ...
's
Tetrarchy
The Tetrarchy was the system instituted by Roman Emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles throughout history. Often when ...
, the traditional seniorities were maintained: "Augustus" was reserved for the two senior emperors and "Caesar" for the two junior emperors – each delegated a share of power and responsibility but each an emperor-in-waiting, should anything befall his senior.
As ''
princeps senatus
The ''princeps senatus'' (plural ''principes senatus'') was the first member by precedence of the Roman Senate. Although officially out of the ''cursus honorum
The ''cursus honorum'' (; , or more colloquially 'ladder of offices') was the sequ ...
'' (lit., "first man of the senate"), the emperor could receive foreign embassies to Rome; some emperors (such as Tiberius) are known to have delegated this task to the Senate. In modern terms, these early emperors would tend to be identified as chiefs of state. The office of ''princeps senatus'', however, was not a magistracy and did not entail ''
imperium
In ancient Rome
In historiography
Historiography is the study of the methods of historian
( 484– 425 BC) was a Greek historian who lived in the 5th century BC and one of the earliest historians whose work survives.
A histori ...

''. At some points in the Empire's history, the emperor's power was nominal; powerful
praetorian prefect
The praetorian prefect ( la, praefectus praetorio, el, ) was a high office in the Roman Empire. Originating as the commander of the Praetorian Guard
The Praetorian Guard (Latin
Latin (, or , ) is a classical language belonging to the Itali ...
s,
masters of the soldiers and on a few occasions, other members of the Imperial household including Imperial mothers and grandmothers were the
true source of power.
''Imperator''
The title ''imperator'' dates back to the
Roman Republic
The Roman Republic ( la, Rēs pūblica Rōmāna ) was a state of the classical Roman civilization, run through public
In public relations
Public relations (PR) is the practice of managing and disseminating information from an indiv ...
, when a victorious commander could be hailed as ''imperator'' in the field by his troops. The Senate could then award or withhold the extraordinary honour of a
triumph; the triumphal commander retained the title until the end of his
magistracy.
[''The Oxford Classical Dictionary'', entry 'Imperator', Third Edition, Oxford University Press, 1996.] In Roman tradition, the first triumph was that of Romulus, but the first attested recipient of the title ''imperator'' in a triumphal context is
Aemilius Paulus in 189 BC.
It was a title held with great pride:
Pompey
Gnaeus Pompeius Magnus (; 29 September 106 BC – 28 September 48 BC), known in English as Pompey or Pompey the Great, was a leading Roman
Roman or Romans most often refers to:
*, the capital city of Italy
*, Roman civilization f ...
was hailed ''imperator'' more than once, as was
Sulla
Lucius Cornelius Sulla Felix (; 138–78 BC), commonly known as Sulla, was a Roman general
A general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, or marines
Marines or naval infan ...

, but it was Julius Caesar who first used it permanently – according to Dio, this was a singular and excessive form of flattery granted by the Senate, passed to Caesar's adopted heir along with his name and virtually synonymous with it.
In 38 BC,
AgrippaAgrippa may refer to:
People
* Agrippa (mythology), semi-mythological king of Alba Longa
* Agrippa (astronomer), Greek astronomer from the late 1st century
* Agrippa the Skeptic, Skeptic philosopher at the end of the 1st century
* Agrippa Meneniu ...
refused a triumph for his victories under Octavian's command, and this precedent established the rule that the ''princeps'' should assume both the salutation and title of ''imperator''. It seems that from then on Octavian (later the first emperor Augustus) used ''imperator'' as a first name (''praenomen''): ''Imperator Caesar'' not ''Caesar imperator''. From this the title came to denote the supreme power and was commonly used in that sense.
Otho
Marcus Otho (; born Marcus Salvius Otho; 28 April 32 – 16 April 69) was for three months, from 15 January to 16 April 69. He was the second emperor of the .
A member of a noble family, Otho was initially a friend and courtier of the young ...
was the first to imitate Augustus, but only with
Vespasian
Vespasian (; la, Vespasianus ; 17 November AD 9 – 23/24 June 79) was a Roman emperor who reigned from 69 to 79 AD. The fourth and last emperor who reigned in the Year of the Four Emperors, he founded the Flavian dynasty that ruled the Empire ...

did ''imperator'' (emperor) become the official title by which the ruler of the
Roman Empire
The Roman Empire ( la, Imperium Rōmānum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican
Republican can refer to:
Political ideology
* An advocate of a republic, a type of governme ...

was known.
''Princeps''
The word ''princeps'' (plural ''principes''), meaning "first", was a republican term used to denote the leading citizen(s) of the state. It was a purely honorific title with no attached duties or powers. It was the title most preferred by Augustus as its use implies only primacy, as opposed to another of his titles, ''
imperator
The Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with" ...

'', which implies dominance. ''Princeps'', because of its republican connotation, was most commonly used to refer to the emperor in
Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Republic, it became ...

(although the emperor's actual constitutional position was essentially "pontifex maximus with tribunician power and ''imperium'' superseding all others") as it was in keeping with the façade of the restored Republic; the
Greek#REDIRECT Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece
Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately 10.7 million as of ...
word ''basileus'' ("king") was modified to be synonymous with emperor (and primarily came into favour after the reign of
Heraclius
Heraclius ( el, Ἡράκλειος, ''Hērakleios''; c. 575 – 11 February 641), sometimes called Heraclius I, was the Byzantine emperor
This is a list of the Byzantine emperors from the foundation of Constantinople
la, Constantinop ...
) as the Greeks had no republican sensibility and openly viewed the emperor as a monarch.
In the era of Diocletian and beyond, ''princeps'' fell into disuse and was replaced with ''dominus'' ("lord"); later emperors used the formula ''Imperator Caesar NN. Pius Felix (Invictus) Augustus'': NN representing the individual's personal name; Pius Felix meaning "Pious and Blest"; and Invictus meaning "undefeated". The use of ''princeps'' and ''dominus'' broadly symbolise the differences in the empire's government, giving rise to the era designations "
Principate
The Principate is the name sometimes given to the first period of the Roman Empire
The Roman Empire ( la, Imperium Rōmānum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican
Republ ...
" and "
Dominate
The Dominate, also known as the late Roman Empire is the name sometimes given to the "despotic
Despotism ( el, Δεσποτισμός, ''despotismós'') is a form of government
A government is the system or group of people governing a ...
".
Evolution in Late Antiquity
In 293, following the
Crisis of the Third Century
The Crisis of the Third Century, also known as Military Anarchy or the Imperial Crisis (235–284 AD), was a period in which the Roman Empire nearly collapsed. It ended due to the military victories of Aurelian and with the ascension of Dioclet ...
which had severely damaged Imperial administration, Emperor
Diocletian
Diocletian (; la, Gaius Aurelius Valerius Diocletianus; born Diocles; 22 December c. 244 – 3 December 311) was from 284 to 305. Born to a family of low status in , Diocletian rose through the ranks of the military to become a commander of ...
enacted sweeping reforms that washed away many of the vestiges and façades of republicanism which had characterized the Augustan order in favor of a more frank autocracy. As a result, historians distinguish the Augustan period as the
principate
The Principate is the name sometimes given to the first period of the Roman Empire
The Roman Empire ( la, Imperium Rōmānum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican
Republ ...
and the period from Diocletian to the 7th-century reforms of Emperor Heraclius as the
dominate
The Dominate, also known as the late Roman Empire is the name sometimes given to the "despotic
Despotism ( el, Δεσποτισμός, ''despotismós'') is a form of government
A government is the system or group of people governing a ...
(from the Latin for "lord".)
Reaching back to the oldest traditions of job-sharing in the republic, however, Diocletian established at the top of this new structure the
Tetrarchy
The Tetrarchy was the system instituted by Roman Emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles throughout history. Often when ...
("rule of four") in an attempt to provide for smoother succession and greater continuity of government. Under the Tetrarchy, Diocletian set in place a system of co-emperors, styled "Augustus", and junior emperors, styled "Caesar". When a co-emperor retired (as Diocletian and his co-emperor
Maximian
Maximian ( la, Marcus Aurelius Valerius Maximianus; c. 250 – c. July 310), nicknamed Herculius, was Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a var ...

did in 305) or died, a junior "Caesar" would succeed him and the co-emperors would appoint new Caesars as needed.
The four members of the Imperial college (as historians call the arrangement) shared military and administrative challenges by each being assigned specific geographic areas of the empire. From this innovation, often but not consistently repeated over the next 187 years, comes the notion of an east–west partition of the empire that became popular with historians long after the practice had stopped. The two halves of empire, while often run as ''de facto'' separate entities day-to-day, were always considered and seen, legally and politically, as separate administrative divisions of a single, insoluble ''imperium'' by the Romans of the time.
When emperor
Theodosius I
Theodosius I ( grc-gre, Θεοδόσιος ; 11 January 347 – 17 January 395), also called Theodosius the Great, was Roman emperor from 379 to 395. During his reign, he faced and overcame a war against the Goths and two civil wars, and ...

died, his sons
Arcadius
Flavius Arcadius ( grc-gre, Ἀρκάδιος, Arkádios; 1 January 377 – 1 May 408) was Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of dif ...

and
Honorius, already proclaimed ''augusti'', succeeded him. Eighty-five years later, following Germanic migrations which had reduced the empire's effective control across
Brittania,
Gaul
Gaul ( la, Gallia) was a region of Western Europe
Western Europe is the western region of Europe
Europe is a continent
A continent is any of several large landmasses. Generally identified by convention (norm), convention rat ...

and
Hispania
Hispania ( ; ) was the Roman
Roman or Romans most often refers to:
*, the capital city of Italy
*, Roman civilization from 8th century BC to 5th century AD
*, the people of ancient Rome
*', shortened to ''Romans'', a letter in the New Testame ...

and a series of military
coup d'état
A coup d'état (; French for "blow of state"), often shortened to coup in English, (also known as an overthrow) is a seizure and removal of a government and its powers. Typically, it is an illegal, unconstitutional seizure of power by a politic ...
which drove Emperor
out of Italy, the idea of dividing the position of emperor was formally abolished by Emperor
Zeno
Zeno or Zenon ( grc, Ζήνων) may refer to:
People
* Zeno (name), including a list of people and characters with the name
Philosophers
* Zeno of Elea (), philosopher, follower of Parmenides, known for his paradoxes
* Zeno of Citium (333 – 2 ...
(480).
The Roman Empire survived in the east until 1453, but the marginalization of the former heartland of Italy to the empire had a profound cultural impact on the empire and the position of emperor. The Greek-speaking inhabitants were ''Romaioi'' (Ῥωμαῖοι), and were still considered Romans by themselves and the populations of Eastern Europe, the Near East, India, and China. But many in Western Europe began to refer to the political entity as the "Greek Empire". The evolution of the church in the no-longer imperial city of Rome and the church in the now supreme Constantinople began to follow divergent paths, culminating in the
schism
A schism ( , , or, less commonly, ) is a division between people, usually belonging to an organization, movement, or religious denomination. The word is most frequently applied to a split in what had previously been a single religious body, s ...
between the
Roman Catholic
Roman or Romans most often refers to:
*Rome
, established_title = Founded
, established_date = 753 BC
, founder = King Romulus
, image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Laz ...

and
Eastern Orthodox
The Eastern Orthodox Church, also called the Orthodox Church, is the second-largest Christian church, with approximately 220 million baptised members. It operates as a communion
Communion may refer to:
Religion
* The Eucharist (also cal ...
faiths. The position of emperor was increasingly influenced by Near Eastern concepts of kingship. Starting with Emperor Heraclius, Roman emperors styled themselves "King of Kings" (from the imperial Persian ''
Shahanshah
Shah (; fa, شاه, Šâh or Šāh, , ) was a title given to the emperors and kings of Iran (historically known as "Name of Iran, Persia" in the Western world).Yarshater, EhsaPersia or Iran, Persian or Farsi, ''Iranian Studies'', vol. XXII n ...

'') from 627 and "Basileus" (from the title used by
Alexander the Great
Alexander III of Macedon ( grc-gre, Αλέξανδρος}, ; 20/21 July 356 BC – 10/11 June 323 BC), commonly known as Alexander the Great, was a king (''basileus
''Basileus'' ( el, βασιλεύς) is a Greek term and title
A title ...

) from 629. The later period of the empire is today called the
Byzantine Empire
The Byzantine Empire, also referred to as the Eastern Roman Empire, or Byzantium, was the continuation of the Roman Empire
The Roman Empire ( la, Imperium Rōmānum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn ...

as a matter of scholarly convention.
Titles and positions
Although these are the most common offices, titles, and positions, not all Roman emperors used them, nor were all of them used at the same time in history. The consular and censorial offices especially were not an integral part of the Imperial dignity, and were usually held by persons other than the reigning emperor.
*
Augustus
Caesar Augustus (23 September 63 BC19 August AD 14) was the first Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles through ...
: (also "" or ""), "Majestic" or "Venerable"; an honorific
cognomen
A ''cognomen'' (; plural ''cognomina''; from ''con-'' "together with" and ''(g)nomen'' "name") was the third name of a citizen of , under . Initially, it was a , but lost that purpose when it became hereditary. Hereditary ''cognomina'' were used t ...
exclusive to the emperor
*
Autokrator
''Autokratōr'' ( grc-gre, αὐτοκράτωρ, autokrátōr, self-ruler", "one who rules by himself, , ; grc, αὐτοκράτορες, autokrátores, label=none, from grc, αὐτός, autós, self, label=none + grc, κράτος, krátos, ...
: (, ''Autokratōr''), (lit. "Self-ruler"); Greek title equivalent to ''imperator'' or commander-in-chief
*
Basileus
''Basileus'' ( el, βασιλεύς) is a Greek term and title
A title is one or more words used before or after a person's name, in certain contexts. It may signify either generation, an official position, or a professional or academic quali ...
: (), Greek for
king
King is the title given to a male monarch in a variety of contexts. The female equivalent is queen regnant, queen, which title is also given to the queen consort, consort of a king.
*In the context of prehistory, antiquity and contempora ...

, popularly used in the east to refer to the emperor; a formal title of the Roman emperor beginning with
Heraclius
Heraclius ( el, Ἡράκλειος, ''Hērakleios''; c. 575 – 11 February 641), sometimes called Heraclius I, was the Byzantine emperor
This is a list of the Byzantine emperors from the foundation of Constantinople
la, Constantinop ...
*
Caesar
Gaius Julius Caesar (; 12 July 100 BC – 15 March 44 BC) was a Roman people, Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey Caesar's C ...
: (also ""), "Caesar"; initially the
cognomen
A ''cognomen'' (; plural ''cognomina''; from ''con-'' "together with" and ''(g)nomen'' "name") was the third name of a citizen of , under . Initially, it was a , but lost that purpose when it became hereditary. Hereditary ''cognomina'' were used t ...
of
Julius Caesar
Gaius Julius Caesar (; 12 July 100 BC – 15 March 44 BC) was a Roman
Roman or Romans most often refers to:
*, the capital city of Italy
*, Roman civilization from 8th century BC to 5th century AD
*, the people of ancient Rome
*', shortened ...

, it was transformed into a title; an honorific name later used to identify an emperor-designate
*
Censor
Censor may refer to:
People with the name
*Cato the Elder
Marcus Porcius Cato (; 234–149 BC), also known as Cato the Censor ( la, Censorius), the Elder and the Wise, was a Roman soldier, senator
The Curia Julia in the Roman Forum ">R ...
: a Republican office held jointly by two former consuls every five years for the purpose of conducting the ''
lustrum
A lūstrum (, plural lūstra) was a term for a five-year period in Ancient Rome
In historiography
Historiography is the study of the methods of historian
( 484– 425 BC) was a Greek historian who lived in the 5th century BC and o ...
'' that determined the role of citizens; the censor could audit all other magistrates and all state finances
*
Consul
Consul (abbrev. ''cos.''; Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman ...
: the highest magistracy of the Roman Republic with a one-year term and one coequal officeholder; the consul was the head of state within Rome. The last emperor to be bestowed the title by the Senate was
Constans II
Constans II ( gr, Κώνστας, ''Kōnstas''; 7 November 630 – 15 July 668), nicknamed "the Bearded" (ὁ Πωγωνᾶτος; ''ho Pogonâtos''), was emperor of the Byzantine Empire from 641 to 668. He was the last attested emperor to serve ...
, who was also the last emperor to visit Rome.
*
Dominus ("Lord" or "Master"): an honorific title mainly associated with the Dominate
* Dominus Noster ("Our Lord"): an honorific title; the praenomen of later emperors.
*
Imperator
The Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with" ...

("Commander" or "Commander-in-Chief"): a
victory title
A victory title is an honorific title adopted by a successful military commander to commemorate his defeat of an enemy nation. The practice was first used by Ancient Rome and is still most commonly associated with the Romans, but it was also adopt ...
taken on accession to the purple and after a major military victory
* Imperator Destinatus ("Destined to be Emperor"): heir apparent, used by
Septimius Severus
Lucius Septimius Severus (; 11 April 145 – 4 February 211) was Roman emperor from 193 to 211. He was born in Leptis Magna (present day Al-Khums, Libya) in the Roman province of Africa (Roman province), Africa. As a young man he advanced thro ...
for
Caracalla
Caracalla ( ; 4 April 188 – 8 April 217), formally known as Antoninus (Marcus Aurelius Antoninus), was Roman emperor from 198 to 217. He was a member of the Severan dynasty, the elder son of Septimius Severus and Julia Domna. Co-ruler ...

* Invictus ("Unconquered"), an honorific title.
*
Nobilissimus
''Nobilissimus'' (Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Rom ...
: (, ''Nōbelissimos''), ("Most Noble"), one of the highest imperial titles held by the emperor
*
Pater Patriae ("Father of the Fatherland"): an honorific title
*
Perpetuus ("Universal"): an honorific title of later emperors
* Pius Felix ("Pious and Blessed"): an honorific title
* Pontifex Maximus ("Supreme Pontiff" or "Chief Priest"): in the Republican era, the Pontifex Maximus was the head of the
College of Pontiffs
The College of Pontiffs ( la, Collegium Pontificum; see ''collegium
A (plural ), or college, was any association in ancient Rome with a legal personality. Such associations could be civil or religious.
The word literally means "society", f ...
, the religious body that oversaw the ancestral public religion of the Romans; Julius Caesar had become Pontifex Maximus before he was elected consul, and the precedent set by his heir Augustus in consolidating supreme authority through this religious office was in general followed by his successors until the empire came under Christian rule
*
Princeps
Princeps (plural: principes) is a Latin word meaning "first in time or order; the first, foremost, chief, the most eminent, distinguished, or noble; the first man, first person". As a title, "princeps" originated in the Roman Republic wherein the ...
("First Citizen" or "Leading Citizen"): an honorific title denoting the status of the emperor as Primus inter pares, first among equals, associated mainly with the Principate
* Princeps Iuventutis: ("Prince of Youth"), an honorific title awarded to a presumptive emperor-designate
* Princeps Senatus: ("First Man of the Senate"), a Republican office with a five-year term
* Sebastos: (), ("Venerable"); the Greek rendition of the imperial title ''Augustus''
* Sebastokrator: (, ''Sebastokratōr''), ("Venerable Ruler); a senior court title from the compound words "sebastos" ("venerable", the Greek equivalent of the Latin ''Augustus'') and "kratōr" ("ruler", the same element as is found in "autokratōr", "emperor")
* Tribune, Tribunicia Potestas: ("Tribunician Power"); the powers of a tribune of the people, including sacrosanctity and inviolability of his person, and the veto over any decision by any other magistrate, assembly, or the Senate (the emperor could not ''be'' a "tribune" because a tribune was a plebeian by definition, therefore the emperor had all the powers of a tribune without actually being one)
Powers
When Augustus established the ''Princeps'', he turned down supreme authority in exchange for a collection of various powers and offices, which in itself was a demonstration of his ''
auctoritas
300px, Representation of a sitting of the Roman Senate: Cicero attacks Catilina, Catiline, from a 19th-century fresco
''Auctoritas'' is a Latin word which is the origin of English "authority". While historically its use in English was restricted ...
'' ("authority"). As holding ''
princeps senatus
The ''princeps senatus'' (plural ''principes senatus'') was the first member by precedence of the Roman Senate. Although officially out of the ''cursus honorum
The ''cursus honorum'' (; , or more colloquially 'ladder of offices') was the sequ ...
'', the emperor declared the opening and closure of each Senate session, declared the Senate's agenda, imposed rules and regulation for the Senate to follow, and met with foreign ambassadors in the name of the Senate. Being ''
pontifex maximus
The (Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', meaning "to share" or "to be in relation w ...
'' made the emperor the chief administrator of religious affairs, granting him the power to conduct all religious ceremonies, consecrate temples, control the Roman calendar (adding or removing days as needed), appoint the vestal virgins and some flamens, lead the College of Pontiffs, Collegium Pontificum, and summarize the dogma of the Religion in ancient Rome, Roman religion.
While these powers granted the emperor a great deal of personal pride and influence, they did not include legal authority. In 23 BC, Augustus gave the emperorship its legal power. The first was ''tribune, Tribunicia Potestas'', or the powers of the tribune of the plebs without actually holding the office (which would have been impossible, since a tribune was by definition a plebeian, whereas Augustus, although born into a plebeian family, had become a
patrician
Patrician may refer to:
* Patrician (ancient Rome), the original aristocratic families of ancient Rome, and a synonym for "aristocratic" in modern English usage
* Patrician (post-Roman Europe), the governing elites of cities in parts of medieval a ...
when he was adopted into the Julia (gens), ''gens Julia''). This endowed the emperor with inviolability (sacrosanctity) of his person, and the ability to pardon any civilian for any act, criminal or otherwise. By holding the powers of the tribune, the emperor could prosecute anyone who interfered with the performance of his duties. The emperor's tribuneship granted him the right to convene the Senate at his will and lay proposals before it, as well as the ability to
veto
A veto (Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Re ...
any act or proposal by any magistrate, including the actual tribune of the plebeians. Also, as holder of the tribune's power, the emperor would convoke the Roman assemblies, Council of the People, lay legislation before it, and served as the council's president. But his tribuneship only granted him power within Rome itself. He would need another power to veto the act of governors and that of the consuls while in the provinces.
To solve this problem, Augustus managed to have the emperor be given the right to hold two types of
imperium
In ancient Rome
In historiography
Historiography is the study of the methods of historian
( 484– 425 BC) was a Greek historian who lived in the 5th century BC and one of the earliest historians whose work survives.
A histori ...

. The first being ''consul, consular imperium'' while he was in Rome, and ''
'' outside of Rome. While inside the walls of Rome, the reigning consuls and the emperor held equal authority, each being able to veto each other's proposals and acts, with the emperor holding all of the consul's powers. But outside of Rome, the emperor outranked the consuls and could veto them without the same effects on himself. Imperium Maius also granted the emperor authority over all the Roman province, provincial Roman Governor, governors, making him the ultimate authority in provincial matters and gave him the supreme command of all of Rome's Roman legion, legions. With Imperium Maius, the emperor was also granted the power to appoint governors of imperial provinces without the interference of the Senate. Also, Imperium Maius granted the emperor the right to veto the governors of the provinces and even the reigning consuls while in the provinces.
Normally, the powers vested in Augustus would have been split between several people, who would each exercise them with the assistance of a colleague and for a specific period of time. Augustus held them all at once by himself, and with no time limits; even those that nominally had time limits were automatically renewed whenever they lapsed.
Lineages and epochs
Principate
The nature of the imperial office and the
Principate
The Principate is the name sometimes given to the first period of the Roman Empire
The Roman Empire ( la, Imperium Rōmānum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican
Republ ...
was established under Julius Caesar's heir and posthumously adopted son, Augustus, and his own heirs, the descendants of his wife Livia from her first marriage to a scion of the distinguished Claudius, Claudian clan. This Julio-Claudian dynasty came to an end when the Emperor Nero – a great-great-grandson of Augustus through his daughter and of Livia through her son – was deposed in 68.
Nero was followed by a succession of usurpers throughout 69, commonly called the "Year of the four emperors, Year of the Four Emperors". The last of these,
Vespasian
Vespasian (; la, Vespasianus ; 17 November AD 9 – 23/24 June 79) was a Roman emperor who reigned from 69 to 79 AD. The fourth and last emperor who reigned in the Year of the Four Emperors, he founded the Flavian dynasty that ruled the Empire ...

, established his own Flavian dynasty. Nerva, who replaced the last Flavian emperor, Vespasian's son Domitian, in 96, was elderly and childless, and chose therefore to adoption, adopt an heir, Trajan, from outside his family. When Trajan acceded to the purple he chose to follow his predecessor's example, adopting Hadrian as his own heir, and the practice then became the customary manner of imperial succession for the next century, producing the "Nerva–Antonine dynasty#Five Good Emperors, Five Good Emperors" and the Empire's period of greatest stability.
The last of the Good Emperors, Marcus Aurelius, chose his natural son Commodus as his successor rather than adopting an heir. A brief period of instability quickly gave way to
Septimius Severus
Lucius Septimius Severus (; 11 April 145 – 4 February 211) was Roman emperor from 193 to 211. He was born in Leptis Magna (present day Al-Khums, Libya) in the Roman province of Africa (Roman province), Africa. As a young man he advanced thro ...
, who established the Severan dynasty which, except for an interruption in 217–218 when Macrinus was emperor, held the purple until 235.
Crisis of the Third Century
The accession of Maximinus Thrax marks both the close and the opening of an era. It was one of the last attempts by the increasingly impotent Roman Senate to influence the succession. Yet it was the second time that a man had achieved the purple while owing his advancement purely to his military career; both
Vespasian
Vespasian (; la, Vespasianus ; 17 November AD 9 – 23/24 June 79) was a Roman emperor who reigned from 69 to 79 AD. The fourth and last emperor who reigned in the Year of the Four Emperors, he founded the Flavian dynasty that ruled the Empire ...

and
Septimius Severus
Lucius Septimius Severus (; 11 April 145 – 4 February 211) was Roman emperor from 193 to 211. He was born in Leptis Magna (present day Al-Khums, Libya) in the Roman province of Africa (Roman province), Africa. As a young man he advanced thro ...
had come from noble or middle-class families, while Thrax was born a commoner. He never visited the city of Rome during his reign, which marks the beginning of a series of "barracks emperors" who came from the army. Between 235 and 285 over a dozen emperors achieved the purple, but only Valerian (emperor), Valerian and Carus managed to secure their own sons' succession to the throne; both dynasties died out within two generations.
Dominate
The accession on 20 November 284, of
Diocletian
Diocletian (; la, Gaius Aurelius Valerius Diocletianus; born Diocles; 22 December c. 244 – 3 December 311) was from 284 to 305. Born to a family of low status in , Diocletian rose through the ranks of the military to become a commander of ...
, the lower-class, Greek-speaking Dalmatia (Roman province), Dalmatian commander of Carus' and Numerian's household cavalry (''protectores Domesticus (Roman Empire), domestici''), marked major innovations in Rome's government and constitutional theory. Diocletian, a traditionalist and religious conservative, attempted to secure efficient, stable government and a peaceful succession with the establishment of the
Tetrarchy
The Tetrarchy was the system instituted by Roman Emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles throughout history. Often when ...
. The empire was divided into East and West, each ruled by an Augustus assisted by a
Caesar
Gaius Julius Caesar (; 12 July 100 BC – 15 March 44 BC) was a Roman people, Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey Caesar's C ...
as emperor-in-waiting. These divisions were further subdivided into new or reformed provinces, administered by a complex, hierarchic bureaucracy of unprecedented size and scope. Diocletian's own court was based at Nicomedia. His co-Augustus, Maximian, was based at Milan, Mediolanum (modern Milan). Their courts were peripatetic, and Imperial progressions through the provinces made much use of the impressive, theatrical Adventus (ceremony), adventus, or "Imperial arrival" ceremony, which employed an elaborate choreography of etiquette to emphasise the emperor's elevation above other mortals. Hyperinflation of imperial honours and titles served to distinguish the ''Augusti'' from their ''Caesares'', and Diocletian, as senior ''Augustus'', from his colleague Maximian. The senior ''Augustus'' in particular was made a separate and unique being, accessible only through those closest to him. The overall unity of the Empire still required the highest investiture of power and status in one man.
The Tetrarchy ultimately degenerated into civil war, but the eventual victor, Constantine I, Constantine the Great, restored Diocletian's division of Empire into East and West. He kept the East for himself and founded his city of
Constantinople
la, Constantinopolis ota, قسطنطينيه
, alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse
Old Norse, Old Nordic, or Old Scandinavian is a stage of development of North Germa ...

as its new capital. Constantine's own dynasty was also soon swallowed up in civil war and court intrigue until it was replaced, briefly, by Julian the Apostate's general Jovian (Emperor), Jovian and then, more permanently, by Valentinian I and the dynasty he founded in 364. Though a soldier from a low middle-class background, Valentinian was made emperor by a conclave of senior generals and civil officials.
Theodosius I
Theodosius I ( grc-gre, Θεοδόσιος ; 11 January 347 – 17 January 395), also called Theodosius the Great, was Roman emperor from 379 to 395. During his reign, he faced and overcame a war against the Goths and two civil wars, and ...

acceded to the purple in the East in 379 and in the West in 394. He outlawed paganism and made Christianity the Empire's official religion. He was the last emperor to rule over a united Roman Empire; the distribution of the East to his son
Arcadius
Flavius Arcadius ( grc-gre, Ἀρκάδιος, Arkádios; 1 January 377 – 1 May 408) was Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of dif ...

and the West to his son
Honorius after his death in 395 represented a permanent division.
Decline of the Western Roman Empire
In the Western Roman Empire, the office of emperor soon degenerated into being little more than a puppet of a succession of
Germanic
Germanic may refer to:
* Germanic peoples, an ethno-linguistic group identified by their use of the Germanic languages
** List of ancient Germanic peoples and tribes
* Germanic languages
:* Proto-Germanic language, a reconstructed proto-language of ...

tribal Monarch, kings, until finally the Heruli Odoacer simply overthrew the child-emperor
Romulus Augustulus
Romulus Augustus ( 465 – after 511?), nicknamed Augustulus, was Roman emperor
The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles throughout ...
in 476, shipped the imperial regalia to the Emperor Zeno in Constantinople and became King of Italy.
Though during his own lifetime Odoacer maintained the legal fiction that he was actually ruling Italy as the viceroy of Zeno, historians mark 476 as the traditional date of the fall of the Western Roman Empire. Large parts of Italy (Sicily, the south part of the peninsula, Ravenna, Venice etc.), however, remained under actual imperial rule from Constantinople for centuries, with imperial control slipping or becoming nominal only as late as the 11th century. In the East, the Empire continued until the fall of
Constantinople
la, Constantinopolis ota, قسطنطينيه
, alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse
Old Norse, Old Nordic, or Old Scandinavian is a stage of development of North Germa ...

to the Ottoman Empire, Ottoman Turks in 1453. Although known as the Byzantine Empire by contemporary historians, the Empire was simply known as the Roman Empire to its citizens and neighboring countries.
Post-classical assertions to the title
Survival of the Roman Empire in the East

The line of Roman emperors in the Eastern Roman Empire continued unbroken at
Constantinople
la, Constantinopolis ota, قسطنطينيه
, alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse
Old Norse, Old Nordic, or Old Scandinavian is a stage of development of North Germa ...

until the Siege of Constantinople (1204), capture of Constantinople in 1204 by the Fourth Crusade. In the wake of this action, four lines of Emperors emerged, each claiming to be the legal successor: the Empire of Thessalonica, evolving from the Despotate of Epirus, which was reduced to impotence when its founder Theodore Komnenos Doukas was Battle of Klokotnitsa, defeated, captured and blinded by the Bulgarian Emperor Ivan Asen III; the Latin Empire, which came to an end when the Empire of Nicaea recovered Constantinople in 1261; the
Empire of Trebizond
The Empire of Trebizond, or Trapezuntine Empire, was a monarchy
A monarchy is a form of government in which a person, the monarch
A monarch is a head of stateWebster's II New College DictionarMonarch Houghton Mifflin. Boston. 2001 ...
, whose importance declined over the 13th century, and whose claims were simply ignored; and the Empire of Nicaea, whose claims based on kinship with the previous emperors, control of the Ecumenical Patriarch of Constantinople, Patriarch of Constantinople, and possession of Constantinople through military prowess, prevailed. The successors of the emperors of Nicaea continued until the fall of Constantinople in 1453 under
Constantine XI Palaiologos
Constantine XI Dragases Palaiologos or Dragaš Palaeologus ( el, Κωνσταντῖνος Δραγάσης Παλαιολόγος, ''Kōnstantînos Dragásēs Palaiológos''; 8 February 1405 – 29 May 1453) was the last List of Byzantine emp ...
.
These emperors eventually normalized the imperial dignity into the modern conception of an emperor, incorporated it into the constitutions of the state, and adopted the aforementioned title ''Basileus kai
autokratōr Rhomaiōn'' ("Emperor and Autocrat of the Romans"). They had also ceased to use Latin as the language of state after Emperor Heraclius (d. 641 AD). Historians have customarily treated the state of these later Eastern emperors under the name "Byzantine Empire". It is important to note, however, that the adjective ''Byzantine'', although historically used by Eastern Roman authors in a metonymic sense, was never an official term.
Last Roman emperor
Constantine XI Palaiologos was the last reigning Roman emperor. A member of the Palaiologos, Palaiologos dynasty, he ruled the remnant of the Eastern Roman Empire from 1449 until his death in 1453 defending its capital Constantinople.
He was born in Mystras, Mystra as the eighth of ten children of Manuel II Palaiologos and Helena Dragaš, the daughter of the Serbs, Serbian prince Constantine Dragaš of Kumanovo. He spent most of his childhood in Constantinople under the supervision of his parents. During the absence of his John VIII Palaiologos, older brother in Italy, Constantine was regent in Constantinople from 1437 to 1440.
Before the beginning of the Fall of Constantinople, siege, Mehmed the Conqueror made an offer to Constantine XI. In exchange for the surrender of Constantinople, the emperor's life would be spared and he would continue to rule in Mystra. Constantine refused this offer. Instead he led the defense of the city and took an active part in the fighting along the Walls of Constantinople, land walls. At the same time, he used his diplomatic skills to maintain the necessary unity between the Genovese, Venetian, and Byzantine troops. As Fall of Constantinople, the city fell on May 29, 1453, Constantine is said to have remarked: "The city is fallen but I am alive." Realizing that the end had come, he reportedly discarded his purple cloak and led his remaining soldiers into a Last stand, final charge, in which he was killed. With his death, Roman imperial succession came to an end, almost 1500 years after Augustus.
Holy Roman Empire

The concept of the Roman Empire was renewed in the West with the coronation of the king of the Franks, Charlemagne (Charles the Great), as Roman emperor by the Pope on Christmas, Christmas Day, 800. This coronation had its roots in the decline of influence of the Pope in the affairs of the Byzantine Empire at the same time the Byzantine Empire declined in influence over politics in the West. The Pope saw no advantage to be derived from working with the Byzantine Empire, but as George Ostrogorsky points out, "an alliance with the famous conqueror of the Lombards, on the other hand ... promised much".
The immediate response of the Eastern Roman emperor was not welcoming. "At that time it was axiomatic that there could be only one Empire as there could be only one church", writes Ostrogorsky. "The coronation of Charles the Great violated all traditional ideas and struck a hard blow at Byzantine interests, for hitherto Byzantium, the new Rome, had unquestionably been regarded as the sole Empire which had taken over the inheritance of the old Roman ''imperium''. Conscious of its imperial rights, Byzantium could only consider the elevation of Charles the Great to be an act of usurpation."
Nikephoros I chose to ignore Charlemagne's claim to the imperial title, clearly recognizing the implications of this act. According to Ostrogorsky, "he even went so far as to refuse the Patriarch Nicephorus permission to dispatch the customary ''synodica'' to the Pope." Meanwhile, Charlemagne's power steadily increased: he subdued Istria and several Dalmatian cities during the reign of Irene of Athens, Irene, and his son Pepin of Italy, Pepin brought Venice under Western hegemony, despite a successful counter-attack by the Byzantine fleet. Unable to counter this encroachment on Byzantine territory, Nikephoros' successor Michael I Rangabe capitulated; in return for the restoration of the captured territories, Michael sent Byzantine delegates to Aachen in 812 who recognized Charlemagne as ''Basileus''. Michael did not recognize him as ''Basileus'' of the Romans, however, which was a title that he reserved for himself.
[Eichmann, Eduard (1942)]
''Die Kaiserkrönung im Abendland: ein Beitrag zur Geistesgeschichte des Mittelalters, mit besonderer Berücksichtigung des kirchlichen Rechte, der Liturgie und der Kirchenpolitik''
Echter-Verlag. p. 33.
This line of Roman emperors was actually generally
Germanic
Germanic may refer to:
* Germanic peoples, an ethno-linguistic group identified by their use of the Germanic languages
** List of ancient Germanic peoples and tribes
* Germanic languages
:* Proto-Germanic language, a reconstructed proto-language of ...

rather than Roman. These emperors used a variety of titles (most frequently "''Imperator Augustus''") before finally settling on ''Imperator Romanus Electus'' ("Elected Roman Emperor"). Historians customarily assign them the title "Holy Roman Emperor", which has a basis in actual historical usage, and treat their "
Holy Roman Empire
The Holy Roman Empire ( la, Sacrum Romanum Imperium; german: Heiliges Römisches Reich) was a multi-ethnic complex of territories in Western
Western may refer to:
Places
*Western, Nebraska, a village in the US
*Western, New York, a town i ...
" as a separate institution. To Latin Catholics of the time, the Pope was the temporal authority as well as spiritual authority, and as Bishop of Rome he was recognized as having the power to anoint or crown a new Roman emperor. The last man to be crowned by the pope (although in Bologna, not Rome) was Charles V, Holy Roman Emperor, Charles V. All his successors bore only a title of "Elected Roman Emperor".
This line of Emperors lasted until 1806 when Francis II, Holy Roman Emperor, Francis II dissolved the Empire during the Napoleonic Wars. Despite the existence of later potentates styling themselves "emperor", such as the Napoleons, the Habsburg Austrian Empire, Emperors of Austria, and the Hohenzollern German Empire, heads of the German Reich, this marked the end of the Holy Roman Empire.
See also
* Imperial cult of ancient Rome
* Interregnum
* Justitium
* Roman Emperors family tree
** Julio-Claudian family tree
** Severan dynasty family tree
* Roman usurper
Lists
* List of Roman emperors
* List of Byzantine emperors
* List of Roman usurpers
* List of condemned Roman emperors
* List of Imperial Roman victory titles
References
Citations
Sources
*
*
*
*
*
*
*
*
*
Further reading
* Scarre, Chris. ''Chronicle of the Roman Emperors: The Reign-by-Reign Record of the Rulers of Imperial Rome''. London: Thames & Hudson, October 1, 1995. (hardcover).
External links
De Imperatoribus Romanis by Kelley L. Ross, Ph.D.
UNRV.comThe Roman Law LibraryList of Greatest Roman Emperors
{{Ancient Rome topics
27 BC establishments
20s BC establishments in the Roman Empire
1453 disestablishments
15th-century disestablishments in the Byzantine Empire
Roman emperors,
Ancient Roman titles, Emperor, Roman
Positions of authority