The detailed account on the history of the Proto-Bulgarian people, their wanderings from the Sea of Azov and Kuban basin over the North shore of Pontus Euxeinos and eventual settlement in Byzantine Thrace looks like an isolated piece of text everywhere it is found in the works of Byzantine historians. The aim of the article is to show that stylistic considerations make it hardly possible to associate this fragment with either of the two hypothetic lost sources which covered Byzantine history of 685–718 and 717–775. The manner in which the text is written betrays provenance from the imperial chancellery.