The modern Bulgarian nation is a mixture of three ethnic groups: Thracians, Slavs and Bulgarians (Proto-Bulgarians).
The Thracians are the earliest recorded population in the eastern half of the Balkan Peninsula, in what is today Bulgaria. Judging from the Homer's epic poems, the name Thracian appeared first in late 2nd millennium BC. The Thracians were numerous people scattered over a vast territory. Throughout history the Thracians who were famous artisans did not invent their own alphabet and used Greek letters. But the people who endowed the world with Orpheus and Spartacus possessed an exceptionally original culture.
The Slavs that settled in the Balkans were unwary people, mainly land tillers and stock-breeders, with some knowledge of metalworking, weaving and pottery. The Slav religion was polytheistic. They settled in the lands to the south of the Danube River in 6th – 7th c. in such large numbers that the Byzantine Empire largely lost control on most of the peninsula. The Slavicizing of the Balkans played a definite catalytic role promoting the development of relations of production and causing changes in the social system of the Byzantium itself owing to which the Eastern Roman Empire outlived the Western by a millennium.
The Bulgarians (Proto-Bulgarians) appeared on the stage of history in the swirl of the Great Migrations (4th – 6th c.), the common madness that destroyed the ancient world. Their homeland was somewhere in Central Asia. The main god of Proto-Bulgarians was Tangra. They had a perfect lunar calendar to count the days of life. The Great Migrations that started in the second half of the IVth century tangibly split this ethnic group, not sparing the Proto-Bulgarians tribal alliance called Great Bulgaria, led by Khan Kubrat. After his death some of the Proto-Bulgarians led by his son Asparuh moved westwards and c.660 settled adjoining Byzantium. The union of Asparuh's people in 681 with the Slav tribes in Moesia laid the beginnings of the eventful history of Medieval Bulgaria.