Bulgarian suzerainty over the region was established by khan Presian in 837, when a military campaign led by his kavkhanIsbul gave Bulgaria control over most of Macedonia and the Rhodopes.
By the early 19th century, the Moratsi had transofrmed into a Bulgarian ethnographic group known under the name of Marvatsi (Marvaks), who lived around Melnik and Nevrokop in present-day Bulgaria and in the mountainous parts of the regions of Serres and Demirhisar in modern Greece.[3][4]
^Ангелов, Димитър (1971). Образуване на българската народност [The Formation of the Bulgarian People] (in Bulgarian). Sofia: Наука и изкуство (Nauka i izkustvo). p. 160.
^Колев, Николай (1987). Българска етнография [Bulgarian Ethnography] (in Bulgarian). Sofia: Наука и изкуство (Nauka i izkustvo). p. 53.
^ΚΩΣΤΟΠΟΥΛΟΣ, ΤΑΣΟΣ (2018), Η πολιτική και κοινωνική διάσταση της εθνικής διαπάλης στην ύστερη οθωμανική Μακεδονία [The Political and Social Dimension of the National Struggle in Late Ottoman Macedonia], Mytilene, p. 67{{citation}}: CS1 maint: location missing publisher (link)
^Rumenov, Vladimir (1941). "Българитѣ въ Македония подъ гръцка власть" [The Bulgarians in Greek Macedonia]. Македонски Прегледъ. 4. Sofia: 89.
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