Bulgarians (, ) are a nation and South Slavic ethnic group native to Bulgaria and its neighbouring region, who share a common Bulgarian ancestry, culture, history and language. They form the majority of the population in Bulgaria, while in North Macedonia, Ukraine, Moldova, Serbia, Romania, Hungary, Albania and Greece they exist as historical communities.
Etymology
Bulgarians derive their ethnonym from the Bulgars. Their name is not completely understood and difficult to trace back earlier than the 4th century AD, but it is possibly derived from the Proto-Turkic word *bulģha ("to mix", "shake", "stir") and its derivative *bulgak ("revolt", "disorder"). Alternative etymologies include derivation from a compound of Proto-Turkic (Oghuric) *bel ("five") and *gur ("arrow" in the sense of "tribe"), a proposed division within the Utigurs or Onogurs ("ten tribes").
Citizenship
According to art. 25(1) of Constitution of Bulgaria, a Bulgarian citizen shall be anyone born to at least one parent holding a Bulgarian citizenship, or born on the territory of the Republic of Bulgaria, should they not be entitled to any other citizenship by virtue of origin. Bulgarian citizenship shall further be acquirable through naturalization. About 85% of Bulgaria's population identified themselves as ethnic Bulgarians in 2021 Bulgarian census.
Ethnogenesis
Bulgarians are descended from peoples of vastly different origins and numbers, and are thus the result of a "melting pot" effect. The main ethnic elements which blended in to produce the modern Bulgarian ethnicity are: Thracians – a native ancient Balkan Indo-European people that left a cultural and genetic legacy. Approx. 55% of Bulgarian autosomal genetic legacy is of Paleo-Balkan and Mediterranean origin and can be attributed to Thracian and other indigenous Balkan population predating Slavs and Bulgars; Early Slavs – an Indo-European group of tribes that migrated from Eastern Europe into the Balkans in the 6th–7th century CE and imposed their language and culture on the local Thracian, Roman and Greek communities. Approx. 40% of Bulgarian autosomal make-up comes from a northeastern European population that admixed with the native population in 400–1000 CE; Bulgars – a semi-nomadic tribal federation from Central Asia that settled in the northeast of the Balkans in 7th century CE, federated with the local Slavic and Slavicized population, organised the early medieval Bulgarian statehood and bequeathed their ethnonym to the modern Bulgarian ethnicity, while eventually assimilating into the Slavic population. Approximately 2.3% of Bulgarian genes originate in Central Asia, corresponding to Asian tribes such as the Bulgars, with admixture peaking in the 9th century CE;<ref>Science, 14 February 2014, Vol. 343 no. 6172, p. 751, A Genetic Atlas of Human Admixture History, Garrett Hellenthal at al.: " CIs. for the admixture time(s) overlap but predate the Mongol empire, with estimates from 440 to 1080 CE (Fig.3. )</ref>
The indigenous Thracians left a cultural and genetic legacy. Other pre-Slavic Indo-European peoples, including Dacians (if distinct from Thracians), Celts, Goths, Romans, ancient Greeks, Sarmatians, Paeonians and Illyrians also settled into the later Bulgarian land. The Thracian language was still spoken in the 6th century, probably becoming extinct afterwards,The Oxford Encyclopedia of Ancient Greece and Rome, 7th edition, pp. 57 but that in a later period the Bulgarians replaced long-established Greek/Latin toponyms with Thracian, might suggest that it had not been completely obliterated then. Some pre-Slavic linguistic and cultural traces might have been preserved in modern Bulgarians (and Macedonians).Ancient Languages of the Balkans, Radoslav Katicic, Walter de Gruyter, 1976, , pp. 9–10; 71. Scythia Minor and Moesia Inferior appear to have been Romanized, although the region became a focus of barbarian re-settlements (various Goths and Huns) during the 4th and early 5th centuries AD, before a further "Romanization" episode during the early 6th century. According to archeological evidence from the late periods of Roman rule, the Romans did not decrease the number of Thracians significantly in major cities. By the 4th century the major city of Serdica had predominantly Thracian populace based on epigraphic evidence, which shows prevailing Latino-Thracian given names, but thereafter the names were completely replaced by Christian ones.