Bosnia has been inhabited at least since Neolithic times. In the late Bronze Age, the Neolithic population was replaced by more warlike Indo-European tribes known as the Illyres or Illyrians. Celtic migrations in the 4th and 3rd century BCE displaced many Illyrian tribes from their former lands, but some Celtic and Illyrian tribes mixed. Concrete historical evidence for this period is scarce, but overall it appears that the region was populated by a number of different peoples speaking distinct languages. Conflict between the Illyrians and Romans started in 229 BCE, but Rome wouldn’t complete its annexation of the region until 9 CE. In the Roman period, Latin-speaking settlers from all over the Roman empire settled among the Illyrians and Roman soldiers were encouraged to retire in the region.
Christianity had already arrived in the region by the end of the 1st century, and numerous artifacts and objects from the time testify to this. Following events from the years 337 and 395 when the Empire split, Dalmatia and Pannonia were included in the Western Roman Empire. The region was conquered by the Ostrogoths in 455, and further exchanged hands between the Alans and Huns in the years to follow. By the 6th century, Emperor Justinian had re-conquered the area for the Byzantine Empire. The Slavs, a migratory people from southeastern Europe, were subjugated by the Eurasian Avars in the 6th century, and together they invaded the Eastern Roman Empire in the 6th and 7th centuries, settling in what is now Bosnia and Herzegovina and the surrounding lands. More South Slavs (namely Croats and Serbs) came in a second wave, and according to some scholars were invited by Emperor Heraclius to drive the Avars from Dalmatia.
The Slavic Peoples are an ethnic and linguistic branch of Indo-European peoples, living mainly in central and eastern Europe. From the early 6th century they spread to inhabit most of the Central and Eastern Europe and the Balkans. Many settled later in Siberia and Central Asia or emigrated to other parts of the world. Over half of Europe’s territory is inhabited by Slavic-speaking communities.
Modern nations and ethnic groups called by the ethnonym Slavs are considerably diverse both genetically and culturally, and relations between them – even within the individual ethnic groups themselves – are varied, ranging from a sense of connection to feelings of mutual hostility.
Slavic peoples are classified geographically and linguistically into West Slavic (including Czechs, Moravians, Poles, Silesians, Slovaks and Sorbs), East Slavic (including Belarusians, Russians and Ukrainians), and South Slavic (including Bosniaks, Bulgarians, Pomaks, Croats, Macedonians, Montenegrins, Serbs and Slovenes). For a more comprehensive list, see the section below on ethnocultural subdivisions.
Modern knowledge of Bosnia in the western Balkans during the dark ages is patchy. Upon the looter invasions by the Avar and Slav horsemen from 6th-9th century, bringing Slavic languages (which prompted some to confuse that with the native Illyrian population turning Slav as well), both probably gave way to feudalism only with the might by the Frankish penetrating into the region in the late 9th century (Bosnia probably originated as one such pre-feudal entity). It was also around this time that the Bosnians were Christianized. The region of Bosnia had been part of the kingdoms of Serbia and Croatia, whose borders were often fluctuant. However, by the high middle ages Croatia had been acquired by the Hungarian Kingdom, and the Serbian state to the southeast was in a period of stagnation. Control over Bosnia subsequently was contested between the Kingdom of Hungary and the Byzantine empire. Hungary appointed Ban Boric as the first ruler and Viceroy of Bosnia. Under the pressure of the Byzantine, a subsequent King of Hungary appointed one Kulin as a Ban to rule the province under the eastern vassalage. However, this vassalage was largely nominal.
The second Bosnian ruler, Ban Kulin, allegedly presided over nearly three decades of peace and stability during which he strengthened the country’s economy through treaties with Dubrovnik and Venice. His rule also marked the start of a controversy with the Bosnian Church, an indigenous Christian sect considered heretical by both the Roman Catholic and Eastern Orthodox churches. In response to Hungarian attempts to use church politics regarding the issue as a way to reclaim sovereignty over Bosnia, Kulin held a council of local church leaders to renounce the heresy in 1203. Despite this, Hungarian ambitions remained unchanged long after Kulin’s death in 1204, waning only after an unsuccessful invasion in 1254.
Bosnian history from then until the early 14th century was marked by the power struggle between the Šubić and Kotromanić families. This conflict came to an end in 1322, when Stjepan II Kotromanić became ban. By the time of his death in 1353, he had succeeded in annexing territories to the north and west, as well as Zahumlje and parts of Dalmatia. He was succeeded by his nephew Tvrtko who, following a prolonged struggle with nobility and inter-family strife, gained full control of the country in 1367. Under Tvrtko, Bosnia grew in both size and power, finally becoming an independent kingdom in 1377. Following his death in 1391 however, Bosnia fell into a long period of decline. The Ottoman Empire had already started its conquest of Europe and posed a major threat to the Balkans throughout the first half of the 15th century. Finally, after decades of political and social instability, Bosnia officially fell in 1463, while resistance was active and fierce for a few more centuries.
Herzegovina fell under the Otoman empire in 1482.