Page "History of the Balkans" Paragraph 73

As from the beginning of the 7th century, the fledgling Bulgarian state started to play a more and more important role in the European Southeast.

After defeating the Avars in 804, Khan Krum added to Bulgaria Transylvania, eastern Panonia, Bačka and Srem.

His descendants, Omurtag, Malamir and Presian, continued the Bulgarian territorial expansion southward conquering the inland parts of Thrace and Macedonia.

The addition of these territories strengthened additionally the Slavic element in the Bulgar state and helped the assimilation of the Bulgars by the Slavs.

By the middle of the 9th century, the Bulgars and the Slavs had already to a large extent coalesced to one people — the Bulgarians — through mixed marriages ( even in the royal dynasty, Omurtag was not already married to a Slavic woman but also gave two of his sons Slavic names ) and as a result of the laws of Khan Krum and the abolition of the autonomy of the Slavic tribes undertaken by Omurtag.

The process of coalescence was additionally strengthened by the en masse conversion to Christianity under Boris I Michael ( 864 ) because of the dominant Byzantine influence in Macedonia and Thrace.

At the end of the 9th century Bulgars and Slavs lived as Bulgarians in most of Moesia, northern Thrace and upper inland Macedonia and spoke a Slavic language with a minor admixture of Bulgar words.

The Indo European Bulgar language is now extinct.