Dagalaifus was a Roman army officer of Germanic descent. A pagan, he served as

consul Consul (abbrev. ''cos.''; Latin plural ''consules'') was the title of one of the two chief magistrates of the Roman Republic, and subsequently also an important title under the Roman Empire. The title was used in other European city-states throug ...

in 366. In the year 361, he was appointed by

Emperor Julian Julian ( la, Flavius Claudius Julianus; grc-gre, Ἰουλιανός ; 331 – 26 June 363) was Roman emperor from 361 to 363, as well as a notable philosopher and author in Greek. His rejection of Christianity, and his promotion of Neoplaton ...

as ''

comes domesticorum The origins of the word ''domesticus'' can be traced to the late 3rd century of the Late Roman army. They often held high ranks in various fields, whether it was the servants of a noble house on the civilian side, or a high-ranking military pos ...

'' (Commander of the Household Guard). He accompanied Julian on his march through Illyricum to quell what remained of the government of

Constantius II Constantius II (Latin: ''Flavius Julius Constantius''; grc-gre, Κωνστάντιος; 7 August 317 – 3 November 361) was Roman emperor from 337 to 361. His reign saw constant warfare on the borders against the Sasanian Empire and Germani ...

that year. He led a party into

Sirmium Sirmium was a city in the Roman province of Pannonia, located on the Sava river, on the site of modern Sremska Mitrovica in the Vojvodina autonomous provice of Serbia. First mentioned in the 4th century BC and originally inhabited by Illyrians an ...

that arrested the commander of the resisting army, Lucillianus. In the spring of 363, Dagalaifus was part of Julian's ultimately-disastrous invasion of

Persia Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

. On June 26, while still campaigning, Julian was killed in a skirmish. Dagalaifus, who had been with the rear guard, played an important role in the election of the next emperor. The council of military officers (including Dagalaifus) finally agreed on the new ''comes domesticorum'',

Jovian Jovian is the adjectival form of Jupiter and may refer to: * Jovian (emperor) (Flavius Iovianus Augustus), Roman emperor (363–364 AD) * Jovians and Herculians, Roman imperial guard corps * Jovian (lemur), a Coquerel's sifaka known for ''Zoboomafo ...

, to succeed Julian. Jovian was a Christian whose father Varronianus had himself once served as ''comes domesticorum''. As emperor, Jovian quickly arranged an end to the Persian hostilities on terms that were far from advantageous to Rome. He appointed Dagalaifus ''

magister equitum The , in English Master of the Horse or Master of the Cavalry, was a Roman magistrate appointed as lieutenant to a dictator. His nominal function was to serve as commander of the Roman cavalry in time of war, but just as a dictator could be nomi ...

'' (commander of the cavalry), where Dagalaifus presumably succeeded the then-restored Lucillianus to that position. Following the death of Jovian after only several months’ rule, Dagalaifus was again influential in the election of Valentinian as the next Roman Emperor. Although he opposed Valentinian's decision to elevate his brother,

Valens Valens ( grc-gre, Ουάλης, Ouálēs; 328 – 9 August 378) was Roman emperor from 364 to 378. Following a largely unremarkable military career, he was named co-emperor by his elder brother Valentinian I, who gave him the eastern half of ...

, as co-emperor, Dagalaifus was retained and presumably continued ''magister equitum'' serving under Valentinian in the

Western Empire The Western Roman Empire comprised the western provinces of the Roman Empire at any time during which they were administered by a separate independent Imperial court; in particular, this term is used in historiography to describe the period fr ...

. In the winter of late 365, Valentinian learned that the

Alemanni The Alemanni or Alamanni, were a confederation of Germanic tribes * * * on the Upper Rhine River. First mentioned by Cassius Dio in the context of the campaign of Caracalla of 213, the Alemanni captured the in 260, and later expanded into pres ...

had crossed the

Rhine ), Surselva, Graubünden, Switzerland , source1_coordinates= , source1_elevation = , source2 = Rein Posteriur/Hinterrhein , source2_location = Paradies Glacier, Graubünden, Switzerland , source2_coordinates= , so ...

and defeated his armies in eastern

Gaul Gaul ( la, Gallia) was a region of Western Europe first described by the Romans. It was inhabited by Celtic and Aquitani tribes, encompassing present-day France, Belgium, Luxembourg, most of Switzerland, parts of Northern Italy (only during ...

around

Moguntiacum Mainz () is the capital and largest city of Rhineland-Palatinate, Germany. Mainz is on the left bank of the Rhine, opposite to the place that the Main joins the Rhine. Downstream of the confluence, the Rhine flows to the north-west, with Mainz ...

(

Mainz Mainz () is the capital and largest city of Rhineland-Palatinate, Germany. Mainz is on the left bank of the Rhine, opposite to the place that the Main (river), Main joins the Rhine. Downstream of the confluence, the Rhine flows to the north-we ...

). This was the beginning of the long Alemannic War that would dominate Valentinian's reign. The emperor initially dispatched Dagalaifus to defeat the invaders. But by the time he arrived, he found the Alemannic forces too scattered to pursue. He was then recalled and replaced with the ''Magister Equitum'',

Jovinus :''Jovinus is a Roman cognomen, most often used for a 5th-century Roman usurper emperor. This article is about the Roman usurper. For the saint, see Saint Jovinus. For the Frankish duke, see Jovinus of Provence.'' For the 4th century Roman general ...

. As reward for his support in elevating Valentinian to the imperial purple in 364, Dagalaifus was appointed by him to the

consulship A consul held the highest elected political office of the Roman Republic ( to 27 BC), and ancient Romans considered the consulship the second-highest level of the ''cursus honorum'' (an ascending sequence of public offices to which politic ...

for 366.Ammianus Marcellinus, Res Gestae XXVII.2.1 He served as consul alongside the emperor's seven-year-old son,

Gratian Gratian (; la, Gratianus; 18 April 359 – 25 August 383) was emperor of the Western Roman Empire from 367 to 383. The eldest son of Valentinian I, Gratian accompanied his father on several campaigns along the Rhine and Danube frontiers and wa ...

. Dagalaifus does not appear again in the available historical records.

References

{{DISPLAYTITLE:Dagalaifus (''magister equitum'') 4th-century Germanic people 4th-century Romans 4th-century Roman consuls Comites domesticorum Germanic warriors Imperial Roman consuls Magistri equitum (Roman Empire)