Thracian Bulgarians in the context of "Bulgarians in Turkey"

Illyrian and Slavic were the commonly used names throughout the Early Modern Period of the Western South Slavic dialects, or, sometimes, of the South Slavic languages as a whole. It was used especially in the territories that were historically associated with Croatia during the modern era, until the 19th century.

The term was most widely used by speakers in Dalmatia, who used it to refer to their own language. It was used by both Catholic and Protestant writers. Some, such as Juraj Šižgorić writing in 1487, extended the term to South Slavic languages as a whole; his views are that "the people from Bohemia to the Adriatic and Black seas down to Epirus speak the same language, Illyrian." 16th-century prelate Antun Vrančić also used the term to embrace all South Slavs, and noted that the people of Belgrade (today in Serbia) spoke Illyrian – ″The local inhabitants who speak the Illyrian language call it Slavni Biograd, which means ‘renowned’ or ‘glorious,’ because of the bravery of its soldiers and officers who after the fall of Smederevo and the Serbian state were able to hold out so long in its defense" – while also applying the term to the language of "Thracians" and "Bulgarians". Writing in 1592, bishop Peter Cedolini applied the term even more widely: he believed all the Slavs had a single common language, which he called Illyrian. Some used the term "Slavic" when writing in proto-Serbo-Croatian and "Illyrian" as a synonym when writing in Romance languages.