Several well-supported theories address the issue of the origin of the Romanians. The Romanian language descends from the Vulgar Latin dialects spoken in the Roman provinces north of the "Jireček Line" (a proposed notional line separating the predominantly Latin-speaking territories from the Greek-speaking lands in Southeastern Europe) in Late Antiquity. The theory of Daco-Roman continuity argues that the Romanians are mainly descended from the Daco-Romans, a people developing through the cohabitation of the native Dacians and the Roman colonists in the province of Dacia Traiana (primarily in present-day Romania) north of the river Danube. The competing immigrationist theory states that the Romanians' ethnogenesis commenced in the provinces south of the river with Romanized local populations (known as Vlachs in the Middle Ages) spreading through mountain refuges, both south to Greece and north through the Carpathian Mountains. According to the "admigration theory", migrations from the Balkan Peninsula to the lands north of the Danube contributed to the survival of a Romance-speaking population in those territories.
Romanians, known by the exonym Vlachs in the Middle Ages, speak a language descended from the Vulgar Latin that was once spoken in south-eastern Europe. Inscriptions from the Roman period prove that a line, known as the "Jireček Line", can be drawn through the Balkan Peninsula, which separated the Latin-speaking northern provinces, including Dacia, Moesia and Pannonia from the southern regions where Greek remained the predominant language. Eastern Romance now has four variants, which are former dialects of a Proto-Romanian language. Daco-Romanian, the official language of Romania, is the most widespread of the four variants. Speakers of the Aromanian language live in scattered communities in Albania, Bulgaria, Greece and Macedonia. Another two, by now nearly extinct variants, Megleno-Romanian and Istro-Romanian, are spoken in some villages in Macedonia and Greece, and in Croatia, respectively.
The territories south of the Danube were subject to the Romanization process for about 800 years, while Dacia province to the north of the river was only for 165 years under Roman rule, which caused "a certain disaccord between the effective process of Roman expansion and Romanization and the present ethnic configuration of Southeastern Europe", according to Lucian Boia. Political and ideological considerations, including the dispute between Hungary and Romania over Transylvania, have also colored these scholarly discussions. Accordingly, theories on the Romanian Urheimat or "homeland" can be divided into two or more groups, including the theory of Daco-Roman continuity of the continuous presence of the Romanians' ancestors in the lands north of the Lower Danube and the opposite immigrationist theory.
Followers of the continuity theory argue that the Romanians descended from the inhabitants of "Dacia Traiana", the one-time province encompassing some regions of present-day Romania for around 165 years. In these scholars' view, the close contacts between the autochthonous Dacians and the Roman colonists led to the formation of the Romanian people because many provincials stayed behind after the Roman Empire abandoned its territories north of the Danube. Thereafter the process of Romanization expanded to Maramureş, Moldavia and other neighboring regions due to the free movement of people across the former imperial borders. The spread of Christianity also contributed to the process, since Latin was the language of liturgy among the Daco-Romans. Although for a millennium migratory peoples invaded the lands now forming Romania, a sedentary Romance-speaking population survived. These lands remained the main "center of Romanization" after the Slavs began to assimilate the Latin-speaking population of the Balkans in the 6th century.
Archaeology probably remains the best source of information about the ethnic constitution of the largest population in southeast Europe. The Romanization of Dacia and the birth of a Daco-Roman people can [...] be considered the first stage in the long process of the formation of the Romanian people, but this stage did not end in 275. It continued until the early 6th century, as long as the empire, still in power along the Danube and in Dobrudja, continued to influence the territory north of the river. The continual circulation of people and goods across the river and back certainly facilitated this.
Scholars who support the immigrationist theory propose that the Romanians descended from the Romanized inhabitants of the provinces to the south of the Danube, which were under Roman rule for more than 500 years. Following the collapse of the empire's frontiers around 620, some of this population moved south to regions where Latin had not been widely spoken, giving rise to the modern Vlach shepherds. Others took refuge in the Balkan Mountains where they adopted an itinerant form of sheep- and goat-breeding. Their mobile lifestyle contributed to their spread in the mountainous zones.
The Romanians' ancestors came into close contact with sedentary Slavic-speaking communities in the 10th century at the latest. They adopted Old Church Slavonic liturgy in the First Bulgarian Empire, and preserved it along with their Orthodox Christian faith even after their northward migration across the Danube began. They were first employed as border guards along the southeastern frontiers of the Kingdom of Hungary and later settled in other sparsely inhabited regions as well. Although sheep-breeding remained their principal economic activity for centuries, their permanent settlements are also documented from the 1330s.
[There] is not a single name of a river, a mountain, or a place in Romania which could prove the plausibility of the survival of a language island, even solely in a smaller territory, from Antiquity to the Middle Ages. Whereas whole Romania is entwined with conclusive geographical names which excludes any form of continuity there.— Schramm, Gottfried (1997)
According to the "admigration theory", proposed by Dimitrie Onciul, the formation of the Romanian people occurred in the former "Dacia Traiana" province, and in the central regions of the Balkan Peninsula. However, the Balkan Vlachs' northward migration ensured that these centers remained in close contact for centuries.
[Centuries] after the fall of the Balkan provinces, a pastoral Latin-Roman tradition served as the point of departure for a Valachian-Roman ethnogenesis. This kind of virtuality – ethnicity as hidden potential that comes to the fore under certain historical circumstances – is indicative of our new understanding of ethnic processes. In this light, the passionate discussion for or against Roman-Romanian continuity has been misled by a conception of ethnicity that is far too inflexible
Three major ethnic groups – the Dacians, Illyrians and Thracians – inhabited the northern regions of Southeastern Europe in Antiquity. However, Dacians are considered by other scientists as belonging to Thracian family. The Illyrians were the first to be conquered by the Romans, who organized their territory into the province of Illyricum around 60 BC. In the lands inhabited by Thracians, the Romans set up the province of Moesia in 15 AD, and Thracia 31 years later. Present-day Dobruja was attached to Moesia in 46.
The Romans annihilated the Dacian kingdom to the north of the Lower Danube under Emperor Trajan in 106. Its western territories were organized into the province of Dacia, but Maramureș and further regions inhabited by the Costoboci, Bastarnae and other tribes remained free of Roman rule. The Romans officially abandoned Dacia under Emperor Aurelian (r. 270–275), who organized a new province bearing the same name ("Dacia Aureliana") south of the Lower Danube. Thereafter, pressure from the Goths forced significant groups of Bastarnae and Carpians to seek asylum in the Roman Empire. Although Roman forts were erected north of the Danube in the 320s, the river became the boundary between the empire and the Goths in the 360s.
Meanwhile, from 313 under the Edict of Milan, the Roman Empire began to transform itself into a Christian state. Roman emperors supported Christian missionaries, including Ulfilas who was consecrated bishop for the lands dominated by the Goths in the 340s. The Huns destroyed all these territories between 376 and 406, but their empire also collapsed in 453. Thereafter the Gepids dominated Banat, Crișana, and Transylvania. Their kings' seat was transferred to Sirmium in the 480s. The Ostrogothic Kingdom annexed Dalmatia in 493, while the Antes, Sclavenes and other tribes made frequent raids against the Balkans. The Roman Empire revived under Emperor Justinian I (r. 527–565), but the Avars, who had subjugated the Gepids, invaded the Balkans from the 580s. In 30 years all Roman troops were withdrawn from the peninsula, where only Dyrrhachium, Thessaloniki and a few other towns remained under Roman rule.
The next arrivals, the Bulgars, established their own state on the Lower Danube in 681. Their territorial expansion accelerated after the collapse of the Avar Khaganate in the 790s. The ruler of the First Bulgarian Empire, Boris I (r. 852–889) converted to Christianity in 864. A synod of the Bulgarian Orthodox Church promoted a liturgy in Old Church Slavonic in 893. Bulgaria was invaded by the Hungarians in 894, but a joint counter-attack by the Bulgars and the Pechenegs – a nomadic Turkic people – forced the Hungarians to find a new homeland in the Carpathian Basin. Historians still debate whether they encountered a Romanian population in the territory. The Byzantines occupied the greater part of Bulgaria under Emperor John I Tzimiskes (r. 969–976). The Bulgars regained their independence during the reign of Samuel (r. 997–1014). However, Emperor Basil II of Byzantium conquered their country around 1018.
The first bishop consecrated for the Hungarians was a Greek from Constantinople, but their supreme ruler, Stephen, was baptized according to the Western rite. Crowned the first king of Hungary in 1000 or 1001, he expanded his rule over new territories, including Banat – which was until that point ruled by Ahtum who had received baptism from Orthodox priests in Vidin. Pecheneg groups, pushed by the Ouzes – a coalition of Turkic nomads – sought asylum in the Byzantine Empire in the 1040s. After the Ouzes there followed the Cumans – also a Turkic confederation – who took control of the Pontic steppes in the 1070s. Thereafter, specific groups, including the Hungarian-speaking Székelys and the Pechenegs, defended the frontiers of the Kingdom of Hungary against them. The arrival of mostly German-speaking colonists in the 1150s also reinforced the Hungarian monarch's rule in the region.
The Byzantine authorities introduced new taxes, provoking an uprising in the Balkan Mountains in 1185. The local Bulgarians and Vlachs achieved their independence and established the Second Bulgarian Empire in coalition with the Cumans. A chieftain of the western Cuman tribes accepted Hungarian supremacy in 1227. The Hungarian expansion towards the Pontic steppes was halted by the large Mongol campaign against Eastern and Central Europe in 1241. Although the Mongols withdrew in a year, their invasion caused destruction throughout the region.
The unification of small polities ruled by local Romanian leaders in Oltenia and Muntenia led to the establishment of a new principality, Wallachia. It achieved independence under Basarab the Founder, who defeated a Hungarian army in the battle of Posada in 1330. A second principality, Moldavia, became independent in the 1360s under Bogdan I, a Romanian nobleman from Maramureș.
As a result of their lack of state organization, Romanians are missing from historical sources older than the second half of the 10th century.  Byzantine authors were the first to write of the Romanians. The 11th-century scholar Kekaumenos wrote of a Vlach homeland situated "near the Danube and [...] the Sava, where the Serbians lived more recently". He associates the Vlachs with the Dacians and the Bessi and with the Dacian king Decebal. Accordingly, historians have located this homeland in several places, including Pannonia Inferior (Bogdan Petriceicu Hașdeu) and "Dacia Aureliana" (Gottfried Schramm). The 12th-century scholar John Kinnamos wrote that the Vlachs "are said to be formerly colonists from the people of Italy".
William of Rubruck wrote that the Vlachs of Bulgaria descended from the Ulac people, who lived beyond Bashkiria. The late 13th-century Hungarian chronicler Simon of Kéza states that the Vlachs used to be the Romans' "shepherds and husbandmen" who "elected to remain behind in Pannonia" when the Huns arrived. An unknown author's Description of Eastern Europe from 1308 likewise states that the Balkan Vlachs "were once the shepherds of the Romans" who "had over them ten powerful kings in the entire Messia and Pannonia".
Poggio Bracciolini, an Italian scholar wrote around 1450 that the Romanians' ancestors had been Roman colonists settled by Emperor Trajan. This view was repeated by Aeneas Sylvius Piccolomini, who stated in his work De Europa (1458) that the Vlachs were a genus Italicum ("an Italian race") and were named after one Pomponius Flaccus, a commander sent against the Dacians. Piccolomini's version of the Vlachs' origin was repeated by many scholars in the subsequent century. According to a modified version of his story, which was recorded by the Transylvanian Saxon Johannes Lebelius in 1542, Trajan "led the Vlachi along with Italian people into the kingdom, spread them all around the Dacian kingdom" and "these people after so many severe fights which they have survived, remained in Dacia, and are now farmers of the land.". Flavio Biondo noted that "the Dacians or Wallachs claim to have Roman origins"; Pietro Ranzano wrote in the 15th century that Vlachs declared themselves "descendants of Italians".  The Hungarian Jesuit Stephan Szántó stated in 1574 that Wallachians are "the offspring of an ancient colony of the Romans that used to be once in Transylvania" and their language (Romandiola or Romaniola) would be understandable by "real Italians".
On the other hand, Laonikos Chalkokondyles—a Byzantine scholar from the second half of the 15th century—stated that he never heard anyone "explain clearly where" the Romanians "came from to inhabit" their lands. Chalkokondyles also wrote that the Romanians were said to have come "from many places and settled that area". The 17th-century Johannes Lucius expressed his concerns about the survival of Romans in a territory exposed to invasions for a millennium.
A legend on the origin of the Moldavians, preserved in the Moldo-Russian Chronicle from around 1505, narrates that one "King Vladislav of Hungary" invited their ancestors to his kingdom and settled them "in Maramureş between the Moreş and Tisa at a place called Crij". Grigore Ureche's Chronicle of Moldavia of 1647 is the first Romanian historical work stating that the Romanians "all come from Rîm" (Rome). In 30 years Miron Costin explicitly connected the Romanians' ethnogenesis to the conquest of "Dacia Traiana". Constantin Cantacuzino stated in 1716 that the native Dacians also had a role in the formation of the Romanian people. However, Petru Maior and other historians of the "Transylvanian School" flatly denied any interbreeding between the natives and the conquerors, claiming that the autochthonous Dacian population which was not eradicated by the Romans fled the territory. The Daco-Roman mixing became widely accepted in the Romanian historiography around 1800. This view is advocated by the Greek-origin historians Dimitrie Philippide (in his 1816 work History of Romania) and Dionisie Fotino, who wrote History of Dacia (1818). The idea was supported by the German historian August Ludwig von Schlözer and was also accepted and taught in the Habsburg Empire, including Hungary until the 1870s,  although the Austrian Franz Joseph Sulzer had by the 1780s rejected any form of continuity north of the Danube, and instead proposed a 13th-century migration from the Balkans.
The development of the theories was closely connected to political debates from the 18th century. The three political "nations" of the Principality of Transylvania (the Hungarians, Saxons and Székelys) enjoyed special privileges, while local legislation emphasized that the Romanians had been "admitted into the country for the public good" and they were only "tolerated for the benefit of the country". When suggesting that the Romanians of Transylvania were the direct descendants of the Roman colonists in Emperor Trajan's Dacia, the historians of the "Transylvanian School" also demanded that the Romanians were to be regarded as the oldest residents of the country. The Supplex Libellus Valachorum – a petition completed by the representatives of the local Romanians in 1791 – explicitly demanded that the Romanians should be granted the same legal status that the three privileged "nations" had enjoyed because the Romanians were of Roman stock.
In the 5th century BC, Herodotus was the first author to write a detailed account of the natives of south-eastern Europe. In connection with a Persian campaign in 514 BC, he mentions the Getae, which he called "the most courageous and upright Thracian tribe". Strabo wrote that the language of the Dacians was "the same as that of the Getae".
Literary tradition on the conquest of Dacia was preserved by 3-4 Roman scholars. Cassius Dio wrote that "numerous Dacians kept transferring their allegiance" to Emperor Trajan before he commenced his war against Decebal. Lucian of Samosata, Eutropius, and Julian the Apostate unanimously attest the memory of a "deliberate ethnic cleansing" that followed the fall of the Dacian state. For instance, Lucian of Samosata who cites Emperor Trajan's physician Criton of Heraclea states that the entire Dacian "people was reduced to forty men". In fact, Thracian or possibly Dacian names represent about 2% of the approximately 3,000 proper names known from "Dacia Traiana". Bitus, Dezibalos and other characteristic Dacian names were only recorded in the empire's other territories, including Egypt and Italy. Constantin Daicoviciu, Dumitru Protase, Dan Ruscu and other historians have debated the validity of the tradition of the Dacians' extermination. They state that it only refers to the men's fate or comes from Eutropius's writings to provide an acceptable explanation for the massive colonisation that followed the conquest. Indeed, Eutropius also reported that Emperor Trajan transferred to the new province "vast numbers of people from all over the Roman world". Onosmatic evidence substantiates his words: about 2,000 Latin, 420 Greek, 120 Illyrian, and 70 Celtic names are known from the Roman period.
Barbarian attacks against "Dacia Traiana" were also recorded. For instance, "an inroad of the Carpi" forced Emperor Galerius's mother to flee from the province in the 240s. Aurelius Victor, Eutropius and Festus stated that Dacia "was lost" under Emperor Gallienus (r. 253–268). The Augustan History and Jordanes refer to the Roman withdrawal from the province in the early 270s. The Augustan History says that Emperor Aurelian "led away both soldiers and provincials" from Dacia in order to repopulate Illyricum and Moesia.
In less than a century, the one-time province was named "Gothia", by authors including the 4th-century Orosius. The existence of Christian communities in Gothia is attested by the Passion of Sabbas, "a Goth by race" and by the martyrologies of Wereka and Batwin, and other Gothic Christians. Large number of Goths, Taifali, and according to Zosimus "other tribes that formerly dwelt among them" were admitted into the Eastern Roman Empire following the invasion of the Huns in 376. In contrast with these peoples, the Carpo-Dacians "were mixed with the Huns". Priscus of Panium, who visited the Hunnic Empire in 448, wrote that the empire's inhabitants spoke either Hunnic or Gothic, and that those who had "commercial dealings with the western Romans" also spoke Latin. He also mentions the local name of two drinks, medos and kam. Emperor Diocletian's Edict on Prices states that the Pannonians had a drink named kamos. Medos may have also been an Illyrian term, but a Germanic explanation cannot be excluded.
The 6th-century author Jordanes who called Dacia "Gepidia" was the first to write of the Antes and Slavenes. He wrote that the Slavenes occupied the region "from the city of Noviodunum and the lake called Mursianus" to the river Dniester, and that the Antes dwelled "in the curve of the sea of Pontus". Procopius wrote that the Antes and the Slaveni spoke "the same language, an utterly barbarous tongue". He also writes of an Antian who "spoke in the Latin tongue". The late 7th-century author Ananias of Shirak wrote in his geography that the Slavs inhabited the "large country of Dacia" and formed 25 tribes. In 2001, Florin Curta argues, that the Slaveni ethnonym may have only been used "as an umbrella-term for various groups living north of the Danube frontier, which were neither 'Antes', nor 'Huns' or 'Avars' ".
The Ravenna Geographer wrote about a Dacia "populated by the [...] Avars", but written sources from the 9th and 10th centuries are scarce. The Royal Frankish Annals refers to the Abodrites living "in Dacia on the Danube as neighbors of the Bulgars" around 824. The Bavarian Geographer locates the Merehanii next to the Bulgars. By contrast, Alfred the Great wrote of "Dacians, who were formerly Goths", living to the south-east of the "Vistula country" in his abridged translation (ca. 890) of Paulus Orosius' much earlier work Historiae Adversus Paganos written around 417.
Emperor Constantine VII's De Administrando Imperio contains the most detailed information on the history of the region in the first decades of the 10th century. It reveals that Patzinakia, the Pechenegs' land was bordered by Bulgaria on the Lower Danube around 950, and the Hungarians lived on the rivers Criş, Mureş, Timiş, Tisa and Toutis at the same time. That the Pechenegs's land was located next to Bulgaria is confirmed by the contemporary Abraham ben Jacob. The 10th-century Muslim scholars, Al-Muqaddasi and Ibn al-Nadim mentioned the Waladj and the Blaghā, respectively in their lists of peoples. The list also refer to the Khazars, Alans, and Greeks, and it is possible that the two ethnonyms refer to Vlachs dwelling somewhere in south-eastern Europe. For instance, the historian Alexandru Madgearu says that Al-Muqaddasi's work is the first reference to Romanians living north of the Danube. Victor Spinei wrote that a runestone which was set up around 1050 contains the earliest reference to Romanians living east of the Carpathians. It refers to Blakumen who killed a Varangian merchant at an unspecified place.
The Gesta Hungarorum from around 1150 or 1200 is the first chronicle to write of Vlachs in the intra-Carpathian regions. Its anonymous author stated that the Hungarians encountered "Slavs, Bulgarians, Vlachs, and the shepherds of the Romans" when invading the Carpathian Basin around 895. He also wrote of Gelou, "a certain Vlach" ruling Transylvania, a land inhabited by "Vlachs and Slavs". In his study on medieval Hungarian chronicles, Carlile Aylmer Macartney concluded that the Gesta Hungarorum did not prove the presence of Romanians in the territory, since its author's "manner is much rather that of a romantic novelist than a historian". In contrast, Alexandru Madgearu, in his monography dedicated to the Gesta, stated that this chronicle "is generally credible", since its narration can be "confirmed by the archaeological evidence or by comparison with other written sources" in many cases.
The late 12th-century chronicle of Niketas Choniates contains another early reference to Vlachs living north of the Danube. He wrote that they seized the future Byzantine emperor, Andronikos Komnenos when "he reached the borders of Halych" in 1164. Thereafter, information on Vlachs from the territory of present-day Romania abounds. For instance, Pope Gregory IX wrote about "a certain people in the Cumanian bishopric called Walati" and their bishops around 1234. A royal charter of 1223 confirming a former grant of land is the earliest official document of Romanians in Transylvania. It refers to the transfer of land previously held by them to the monastery of Cârţa, which proves that this territory had been inhabited by Vlachs before the monastery was founded. According to the next document, the Teutonic Knights received the right to pass through the lands possessed by the Székelys and the Vlachs in 1223. Next year the Transylvanian Saxons were entitled to use certain forests together with the Vlachs and Pechenegs. Simon of Kéza knew that the Székelys "shared with the Vlachs" the mountains, "mingling with them" and allegedly adopting the Vlachs' alphabet.
References to Vlachs living in the lands of secular lords and prelates in the Kingdom of Hungary appeared in the 1270s. First the canons of the cathedral chapter in Alba Iulia received a royal authorization to settle Romanians to their domains in 1276. Thereafter, royal charters attest the presence of Romanians in more counties, for instance in Zărand from 1318, in Bihor and in Maramureș from 1326, and in Turda from 1342.
The words "torna, torna fratre" recorded in connection with a Roman campaign across the Balkan Mountains by Theophylact Simocatta and Theophanes the Confessor evidence the development of a Romance language in the late 6th century. The words were shouted "in native parlance" by a local soldier in 587 or 588. When narrating the rebellion of Kuber and his people against the Avars, the 7th-century Miracles of St. Demetrius mentions that a close supporter of his, Mauros spoke four languages, including "our language" (Greek) and "that of the Romans" (Latin). Kuber led a population of mixed origin – including the descendants of Roman provincials who had been captured in the Balkans in the early 7th century – from the region of Sirmium to Thessaloniki around 681.
John Skylitzes's chronicle contains one of the earliest records on the Balkan Vlachs. He mentions that "some vagabond Vlachs" killed David, one of the four Cometopuli brothers between Kastoria and Prespa in 976. After the Byzantine occupation of Bulgaria, Emperor Basil II set up the autocephalous Archbishopric of Ohrid with the right from 1020 to collect income "from the Vlachs in the whole of theme of Bulgaria".
The late 11th-century Kekaumenos relates that the Vlachs of the region of Larissa had "the custom of having their herds and families stay in high mountains and other really cold places from the month of April to the month of September". A passing remark by Anna Comnena reveals that nomads of the Balkans were "commonly called Vlachs" around 1100. Occasionally, the Balkan Vlachs cooperated with the Cumans against the Byzantine Empire, for instance by showing them "the way through the passes" of the Stara Planina in the 1090s.
Most information on the 1185 uprising of the Bulgars and Vlachs and the subsequent establishment of the Second Bulgarian Empire is based on Niketas Choniates's chronicle. He states that it was "the rustling of their cattle" which provoked the Vlachs to rebel against the imperial government. Besides him, Ansbert, and a number of other contemporary sources refer to the Vlach origin of the Asen brothers who initiated the revolt. Ansbert wrote of "Kalopetrus Flachus".
The Russian Primary Chronicle from 1113 contains possible references to Vlachs in the Carpathian Basin. It relates how the Volokhi seized "the territory of the Slavs" and were later expelled by the Hungarians. Therefore, the Slavs' presence antedates the arrival of the Volokhi in the chronicle's narration. Madgearu and many other historians argue that the Volokhi are Vlachs. However, they have also been identified with either Romans or Franks annexing Pannonia (for instance, by Lubor Niederle and by Gyula Kristó respectively).
The 11th-century Persan writer, Gardizi, wrote about a Christian people called N.n.d.r inhabiting the lands along the Danube. Historian Adolf Armbruster identified this people as Vlachs. In Hungarian, the Bulgarians were called Nándor in the Middle Ages. The Vlachs' pre-eminent role in the Second Bulgarian Empire is demonstrated by Blacia, and other similar denominations under which the new state was mentioned in contemporary sources. The Annales Florolivienses, the first such source, mentions the route of Emperor Frederick I Barbarossa "through Hungary, Russia, Cumania, Vlakhia, Durazzo, Byzantium and Turkey" during his crusade of 1189. The poem Nibelungenlied from the early 1200s mentions one "duke Ramunc of Wallachia" in the retinue of Attila the Hun. The poem alludes to the Vlachs along with the Russians, Greeks, Poles and Pechenegs, and may refer to a "Wallachia" east of the Carpathians. The Icelandic author Snorri Sturluson wrote of a Blokumannaland in his early 13th-century text Heimskringla.
Pope Innocent III used the terms "Vlachia and Bulgaria" jointly when referring to the whole territory of the Second Bulgarian Empire. Similarly, the chronicler Geoffrey of Villehardouin refers to the Bulgarian ruler Kaloyan as "Johanitsa, the king of Vlachia and Bulgaria". William of Rubruck distinguished Bulgaria from Blakia. He states that "Bulgaria, Blakia and Slavonia were provinces of the Greeks", implying that his Blakia was also located south of the Danube. Likewise, the "Vlach lands" mentioned in the works of Abulfeda, Ibn Khaldun and other medieval Muslim authors are identical with Bulgaria.
The identification of the Vlachs and the Bolokhoveni of the Hypatian Chronicle whose land bordered on the Principality of Halych is not unanimously accepted by historians (for instance, Victor Spinei refuses it). However, it is certain that a charter of 1247 of King Béla IV of Hungary lists small Romanian polities existing north of the Lower Danube. Thomas Tuscus mentioned Vlachs fighting against the Ruthenes in 1276 or 1277. The first independent Romanian state, the Principality of Wallachia, was known as Oungrovlachia in Byzantine sources, while Moldavia received the Greek denominations Maurovlachia or Russovlachia.
Tumuli erected for a cremation rite appeared in Oltenia and in Transylvania around 100 BC, thus preceding the emergence of the Dacian kingdom. Their rich inventory has analogies in archaeological sites south of the Danube. Although only around 300 graves from the next three centuries have been unearthed in Romania, they represent multiple burial rites, including ustrinum cremation and inhumation. New villages in the Mureș valley prove a demographic growth in the 1st century BC. Fortified settlements were erected on hilltops, mainly in the Orăştie Mountains, but open villages remained the most common type of settlement. In contrast with the finds of 25,000 Roman denarii and their local copies, imported products were virtually missing in Dacia. The interpretations of Geto-Dacian archaeological findings are problematic because they may be still influenced by methodological nationalism.
The conquering Romans destroyed all fortresses and the main Dacian sanctuaries around 106 AD. All villages disappeared because of the demolition. Roman settlements built on the location of former Dacian ones have not been identified yet. However, the rural communities at Boarta, Cernat, and other places used "both traditional and Roman items", even thereafter. Objects representing local traditions have been unearthed at Roman villas in Aiudul de Sus, Deva and other places as well. A feature of the few types of native pottery which continued to be produced in Roman times is the "Dacian cup", a mostly hand-made mug with a wide rim, which was used even in military centers. The use of a type of tall cooking pot indicates the survival of traditional culinary practices as well.
Colonization and the presence of military units gave rise to the emergence of most towns in "Dacia Traiana": for instance, Ulpia Traiana Sarmizegetusa was founded for veterans, Apulum and Potaissa started to develop as canabae. Towns were the only places where the presence of Christians can be assumed based on objects bearing Christian symbolism, including a lamp and a cup decorated with crosses, which have been dated to the Roman period. Rural cemeteries characterized by burial rites with analogies in sites east of the Carpathians attest to the presence of immigrant "barbarian" communities, for instance, at Obreja and Soporu de Câmpie. Along the northwestern frontiers of the province, "Przeworsk" settlements were unearthed at Boineşti, Cehăluţ, and other places.
Archaeological finds suggest that attacks against Roman Dacia became more intensive from the middle of the 3rd century: an inscription from Apulum hails Emperor Decius (r. 249–251) as the "restorer of Dacia"; and coin hoards ending with pieces minted in this period have been found. Inscriptions from the 260s attest that the two Roman legions of Dacia were transferred to Pannonia Superior and Italy. Coins bearing the inscription "DACIA FELIX" minted in 271 may reflect that Trajan's Dacia still existed in that year, but they may as well refer to the establishment of the new province of "Dacia Aureliana".
|Pre-Roman (5th century BC–1st century AD)||59
|11th century–14th century||47
The differentiation of archaeological finds from the periods before and after the Roman withdrawal is not simple, but Archiud, Obreja, and other villages produced finds from both periods. Towns have also yielded evidence on locals staying behind. For instance, in Ulpia Traiana Sarmizegatusa, at least one building was inhabited even in the 4th century, and a local factory continued to produce pottery, although "in a more restricted range". Roman coins from the 3rd and 4th centuries, mainly minted in bronze, were found in Banat where small Roman forts were erected in the 290s. Coins minted under Emperor Valentinian I (r. 364–375) were also found in Ulpia Traiana Sarmizegetusa, where the gate of the amphitheater was walled at an uncertain date. A votive plate found near a spring at Biertan bears a Latin inscription dated to the 4th century, and has analogies in objects made in the Roman Empire. Whether this donarium belonged to a Christian missionary, to a local cleric or layman or to a pagan Goth making an offering at the spring is still debated by archaeologists.
A new cultural synthesis, the "Sântana de Mureş-Chernyakhov culture", spread through the plains of Moldavia and Wallachia in the early 4th century. It incorporated elements of the "Wielbark culture" of present-day Poland and of local tradition. More than 150 "Sântana de Mureş-Chernyakhov" settlements suggest that the territory experienced a demographic growth. Three sites in the Eastern Carpathians already inhabited in the previous century[note 1] prove the natives' survival as well. Growing popularity of inhumation burials also characterizes the period. "Sântana de Mureş-Chernyakhov" cemeteries from the 4th century were also unearthed in Transylvania. Coin hoards ending with pieces from the period between 375 and 395 unearthed at Bistreţ, Gherla, and other settlements point to a period of uncertainty. Featuring elements of the "Przeworsk" and "Sântana de Mureş-Chernyakhov" cultures also disappeared around 400. Archaeological sites from the next centuries have yielded finds indicating the existence of scattered communities bearing different traditions. Again, cremation became the most widespread burial rite east of the Carpathians, where a new type of building – sunken huts with an oven in the corner – also appeared. The heterogeneous vessel styles were replaced by the more uniform "Suceava-Şipot" archaeological horizon of hand made pottery from the 550s.
In contrast with the regions east of the Carpathians, Transylvania experienced the spread of the "row grave" horizon of inhumation necropolises in the 5th century, also known from the same period in Austria, Bohemia, Transdanubia and Thuringia. At the same time, large villages appeared in Crișana and Transylvania, in most cases in places where no earlier habitation has yet been proven. Moreover, imported objects with Christian symbols, including a fish-shaped lamp from Lipova, and a "Saint Menas flask" from Moigrad, were unearthed. However, only about 15% of the 30 known "row grave" cemeteries survived until the late 7th century. They together form the distinct "Band-Noşlac" group of graveyards which also produced weapons and other objects of Western or Byzantine provenance.
The earliest examples in Transylvania of inhumation graves with a corpse buried, in accordance with nomadic tradition, with remains of a horse were found at Band. The "Gâmbaş group" of cemeteries emerged in the same period, producing weapons similar to those found in the Pontic steppes. Sunken huts appeared in the easternmost zones of Transylvania around 7th century. Soon the new horizon of "Mediaș" cemeteries, containing primarily cremation graves, spread along the rivers of the region. The "Nușfalău-Someşeni" cemeteries likewise follow the cremation rite, but they produced large tumuli with analogies in the territories east of the Carpathians.
In the meantime, the "Suceava-Şipot horizon" disappeared in Moldavia and Wallachia, and the new "Dridu culture" emerged on both sides of the Lower Danube around 700. Thereafter the region again experienced demographic growth. For instance, the number of settlements unearthed in Moldavia grew from about 120 to about 250 from the 9th century to the 11th century. Few graveyards yielding artifacts similar to "Dridu cemeteries" were also founded around Alba Iulia in Transylvania. The nearby "Ciumbrud group" of necropolises of inhumation graves point at the presence of warriors. However, no early medieval fortresses unearthed in Transylvania, including Cluj-Mănăştur, Dăbâca, and Şirioara, can be definitively dated earlier than the 10th century.
Small inhumation cemeteries of the "Cluj group", characterized by "partial symbolic horse burials", appeared at several places in Banat, Crişana, and Transylvania including at Biharia, Cluj and Timişoara around 900. Cauldrons and further featuring items of the "Saltovo-Mayaki culture" of the Pontic steppes were unearthed in Alba Iulia, Cenad, Dăbâca, and other settlements. A new custom of placing coins on the eyes of the dead was also introduced around 1000. "Bijelo Brdo" cemeteries, a group of large graveyards with close analogies in the whole Carpathian Basin, were unearthed at Deva, Hunedoara and other places. The east–west orientation of their graves may reflect Christian influence, but the following "Citfalău group" of huge cemeteries that appeared in royal fortresses around 1100 clearly belong to a Christian population.
Thomas Nägler proposes that a separate "Ciugud culture" represents the Vlach population of southern Transylvania. He also argues that two treasures from Cârțișoara and Făgăraș also point at the presence of Vlachs. Both hoards contain Byzantine coins ending with pieces minted under Emperor John II Komnenos who died in 1143. Tudor Sălăgean proposes that these treasures point at a local elite with "at least" economic contacts with the Byzantine Empire. Paul Stephenson argues that Byzantine coins and jewellery from this period, unearthed at many places in Hungary and Romania, are connected to salt trade.
Fortified settlements built on hill-tops characterized the landscape in Illyricum before the Roman conquest. In addition, huts built on piles formed villages along the rivers Sava and its tributaries. Roman coins unearthed in the northwestern regions may indicate that trading contacts between the Roman Empire and Illyricum began in the 2nd century BC, but piracy, quite widespread in this period, could also contribute to their cumulation. The first Roman road in the Balkans, the Via Egnatia which linked Thessaloniki with Dyrrhachium was built in 140 BC. Byllis and Dyrrhachium, the earliest Roman colonies were founded a century later. The Romans established a number of colonies for veterans and other towns, including Emona, Siscia, Sirmium and Iovia Botivo, in the next four centuries.
Hand-made pottery of local tradition remained popular even after potter's wheel was introduced by the Romans. Likewise, as it is demonstrated by altars dedicated to Illyrian deities at Bihać and Topusko, native cults survived the Roman conquest.  Latin inscriptions on stone monuments prove the existence of a native aristocracy in Roman times. Native settlements flourished in the mining districts in Upper Moesia up until the 4th century. Native names and local burial rites only disappeared in these territories in the 3rd century. In contrast, the frontier region along the Lower Danube in Moesia had already in the 1st century AD transformed into "a secure Roman-only zone" (Brad Bartel), from where the natives were moved.
Emperors born in Illyricum, a common phenomenon of the period, erected a number of imperial residences at their birthplaces. For instance, a palace was built for Maximianus Herculius near Sirmium, and another for Constantine the Great in Mediana. New buildings, rich burials and late Roman inscriptions show that Horreum Margi, Remesiana, Siscia, Viminacium, and other centers of administration also prospered under these emperors. Archaeological research – including the large cemeteries unearthed at Ulpianum and Naissus – shows that Christian communities flourished in Pannonia and Moesia from the 4th century. Inscriptions from the 5th century point at Christian communities surviving the destruction brought by the Huns at Naissus, Viminacium and other towns of Upper Moesia. In contrast, villae rusticae which had been centers of agriculture from the 1st century disappeared around 450. Likewise, forums, well planned streets and other traditional elements of urban architecture ceased to exist. For instance, Sirmium "disintegrated into small hamlets emerging in urban areas that had not been in use until then" after 450. New fortified centers developed around newly erected Christian churches in Sirmium, Novae, and many other towns by around 500. In contrast with towns, there are only two archaeological sites[note 2] from this period identified as rural settlements.
Under Justinian the walls of Serdica, Ulpianum and many other towns were repaired. He also had hundreds of small forts erected along the Lower Danube, at mountain passes across the Balkan Mountains and around Constantinople. Inside these forts small churches and houses were built. Pollen analysis suggest that the locals cultivated legumes within the walls, but no other trace of agriculture have been identified. They were supplied with grain, wine and oil from distant territories, as it is demonstrated by the great number of amphorae unearthed in these sites which were used to transport these items to the forts. Most Roman towns and forts in the northern parts of the Balkans were destroyed in the 570s or 580s. Although some of them were soon restored, all of them were abandoned, many even "without any signs of violence", in the early 7th century.
The new horizon of "Komani-Kruja" cemeteries emerged in the same century. They yielded grave goods with analogies in many other regions, including belt buckles widespread in the whole Mediterranean Basin, rings with Greek inscriptions, pectoral crosses, and weapons similar to "Late Avar" items. Most of them are situated in the region of Dyrrhachium, but such cemeteries were also unearthed at Viničani and other settlements along the Via Egnatia. "Komani-Kruja" cemeteries ceased to exist in the early 9th century. John Wilkes proposes that they "most likely" represent a Romanized population, while Florin Curta emphasizes their Avar features. Archaeological finds connected to a Romance-speaking population have also been searched in the lowlands to the south of the Lower Danube. For instance, Uwe Fiedler mentions that inhumation graves yielding no grave goods from the period between the 680s and the 860s may represent them, although he himself rejects this theory.
The grouping of Dacian, Illyrian and Thracian languages into a Thraco-Illyrian branch of the Indo-European language family, a widespread idea in the first half of the 20th century, has lost popularity because of the lack of convincing evidence. Similarly, the supposed close relationship between Dacian and Thracian remains unproven. There are around 100 Romanian words with a possible substratum origin, but the language from which they were transferred cannot be determined. Around 30% of these words[note 3] represent the specific vocabulary of sheep- and goat-breeding. Moreover, about 70 possible substrate words,[note 4] have Albanian cognates. István Schütz argues that the fact that "the same Albanian phone is represented by multiple phones in Romanian, and the same Romanian phone may derive from different Albanian phones" suggests an "Albanian–Romanian symbiosis" lasting more than one century. Alexandru Madgearu and other scholars refuse this idea, stating that "the common elements are less significant than the differences" between the two languages. Albanian, Romanian and other languages sharing some common morphological and syntactic characteristics form together a supposed "Balkan linguistic union". These common features include the postposed definite articles[note 5] and the merger of the dative case and possessive case. Whether they represent a common substrate language, or convergent development is still a matter of debate among linguists.
Around 20% of the entries of the 1958 edition of the Dictionary of the Modern Romanian have directly been inherited from Latin. For instance, the basic lexicons of religion and of agriculture have been preserved. Some variants of the Eastern Romance languages retained more elements of their Latin heritage than others. For instance, both the Maramureș subdialect of Romanian and Arumanian have preserved the Latin word for sand (arină) instead of standard nisip, a Slavic loanword.
In addition to words of Latin or of possible substratum origin, a great number of loanwords can be detected. Initially, Slavic languages had a major influence on Romanian, but a significant number of words were borrowed from Turkic, Hungarian, Greek or German languages. No loanwords of East Germanic (Gothic or Gepid) origin have so far been proven. Common Slavic and Old Church Slavonic loanwords adopted by all Eastern Romance variants prove that the start of the disintegration of Common Romanian can hardly be dated before the 10th century, and in fact a later dating of Romanian is further confirmed by the fact that most Slavic loans into Romanian derive from Serbian and Bulgarian rather than the preceding "Common Slavic" stage. The number of borrowings exceeds that of the inherited terms in several semantic fields, including that of the natural environment For instance, the names for most species of fish of the Danube[note 6] and of a number of other animals living in Romania[note 7] are of Slavic origin. On the other hand, all neighboring peoples adopted a number of Romanian words connected to goat- and sheep-breeding.
In a work from 1976, the philologist Alexandru Rosetti states that of the basic words used most frequently, 60 percent are of Latin origin and 20 percent are of Slavic origin. Lucian Boia also states that "the essential Romanian vocabulary is to a large degree Latin" 
Place names provide a significant proportion of modern knowledge of the extinct languages of South-eastern Europe. For instance, Drobeta, Napoca, Porolissum, Sarmizegetusa and other settlements in "Dacia Traiana" bore names of local origin. The Romans likewise adopted the native names of the main rivers, including Crisia for the Criş, Maris(os) or Marissos for the Mureș, and Tibiskos for the Timiș.
Although some towns preserved their ancient names[note 8] in South-eastern Europe up until now, the names of all Roman settlements attested in Roman Dacia in Antiquity disappeared. The names of the major rivers[note 9] survived the Roman withdrawal, but their modern forms suggest a Slavic mediation instead of a direct transmission from a native language or Latin to languages now spoken in the territory. For instance, the vowel shift from [a] to [u] or [o] experienced in the case of the rivers Mureş [< Maris], Olt [< Aluta], and Someş [< Samu(m)] is attested in the development of the Slavic languages, but is alien to Romanian and other tongues spoken in their regions. Grigore Nandris states that alone among the rivers in Dacia, the development of the name of the Criş from ancient Crisius would be in line with the phonetical evolution of Romanian, but Gottfried Schramm wrote that its [ʃ] ending could have hardly been inherited from Latin. Based on the Repedea name for the upper course of the Bistrița, Nandris also writes that translation from Romanian into Slavic could also create Romanian hydronyms. Dunărea, the Romanian name of the Danube may have developed from a supposed Geto-Dacian *Donaris form. However, this form is not attested in written sources. Therefore, it is possible that the Romanians' ancestors in this case also adopted a Slavic name.
The longer tributaries of the large rivers in Banat, Crişana and Transylvania had modern names of German, Hungarian, Slavic or Turkic origin, which were also adopted by the Romanians. For instance, the tributaries of the Someșul Mic River bear Hungarian[note 10] or Slavic[note 11] names. Place names of Slavic[note 12] or Hungarian[note 13] origin can be found in great number in medieval royal charters pertaining to Banat, Crișana, Maramureș, and Transylvania. In the mountains between the rivers Arieș and Mureș and in the territory the south of the Târnava Mare River, the Romanians and the Transylvanian Saxons directly (without Hungarian mediation) adopted the Slavic place names. In almost all cases, when parallel Slavic-Hungarian or Slavic-German names are attested,[note 14] Romanians borrowed the Slavic forms, suggesting a long cohabitation of the Romanians and the Slavs or a close relationship between the two ethnic groups, maybe already before the arrival of the Hungarians.
Nucşoara, the earliest toponym of certain Romanian origin in the same regions was recorded in 1359. River names of Slavic origin[note 15] can also be found in the regions east and south of the Carpathians, where Turkic river names[note 16] also abound. On the other hand, the name of the Vlaşca region in Wallachia refers to a Romance-speaking community in Slavic environment.
Place names of Latin origin abound in the region of Lake Shkodër, along the rivers Drin and Fan and other territories to the north of the Viga Egnatia. Gottfried Schramm argues that the names of at least eight towns in the region,[note 17] likewise suggest the one-time presence of a Romance speaking population in their vicinity. Romanian place names can still be detected in Albania, Bulgaria, Greece, Montenegro and Serbia. For example, such names[note 18] are concentrated in the wider region of the river Vlasina both in Bulgaria and Serbia, and in Montenegro and the nearby territories.[note 19]
The use of genetic data to supplement traditional disciplines has now become mainstream. Given the palimpsest nature of modern genetic diversity, more direct evidence has been sought from ancient DNA (aDNA) Although data from southeastern Europe is still at an incipient stage, general trends are already evident. For example, it has shown that the Neolithic revolution imparted a major demographic impact throughout Europe, disproving the Mesolithic adaptation scenario in its pure form. In fact, the arrival of Neolithic farmers might have been in at least two "waves", as suggested by a study which analysed mtDNA sequences from Romanian Neolithic samples.
Another major demographic wave also occurred after 3000 BC from the steppe, postulated to be linked with the expansion of Indo-European languages. Bronze and Iron Age samples from Hungary, Bulgaria and Romania, however, suggest that this impact was less significant in Southeastern Europe than areas north of the Carpathians. In fact, in the abovementioned studies, the Bronze and Iron Age Balkan samples do not cluster with modern Balkan groups, but lie between Sardinians and other southwestern European groups, suggesting later phenomena (i.e. in Antiquity, Great Migration Period) caused shifts in population genetic structure. However, aDNA samples from southeastern Europe remain few, and only further sampling will allow a clear and diachronic overview of migratory and demographic trends.
No detailed analyses exist from the Roman and early medieval periods. Genome-wide analyses of extant populations show that intra-European diversity is a continuum (with the exception of groups like Finns, Sami, Basques and Sardinians). Romanians cluster amidst their Balkan and East European neighbours. However, they generally lie significantly closer to Balkan groups (Serbs, Macedonians, Bulgarians) than to central and eastern Europeans like Hungarians, Czechs, Poles and Ukrainians, and many lie in the center of the Balkan cluster, near Albanians, Greeks, and Bulgarians, while many former Yugoslav populations like Serbs, Croats, and Slovenes may draw closer to central European West Slavs. On autosomal studies, genetic distance of some Romanian samples to some Italians, such as Tuscans, is greater than that of the distance to neighboring Balkan peoples, but can in some cases still be relatively close when considering the overall European population structure; this likely reflects mainly ancient or prehistoric population patterns rather than more recent ties due to linguistic relationships. Geography plays one of the most important roles in determining European population structure.