Uprising of Konstantin and Fruzhin

The Uprising of Konstantin and Fruzhin (Bulgarian: Въстание на Константин и Фружин, Vastanie na Konstantin i Fruzhin) was the earliest Bulgarian uprising against Ottoman rule. It was organized in the early 15th century by two Bulgarian nobles, Fruzhin and his cousin Konstantin, and was supported by a Christian coalition, but failed to liberate Bulgaria.

Information about it is quite scarce and the details continue to be the subject of debate among historians. Almost nothing is known about the course of events; the years of its beginning and end, the exact area of its spread, etc. are controversial. Serbs, Hungarians, and Vlachs took part in the uprising on the side of Konstantin and Fruzin.