Shishman
The Shishman were a medieval Bulgarian dynasty of Cuman origin, descended from Shishman, a boyar who held Vidin as a despot from perhaps the 1270s. He acknowledged Golden Horde suzerainty in 1291 and, after an unsuccessful war against Serbia the next year, ruled Vidin as a Serbian vassal.
His son Michael Shishman, despot of Vidin, was elected tsar by the Bulgarian nobility in 1323 and ruled as Michael Asen III. His wars against Byzantium and Serbia ended in defeat at the Battle of Velbazhd in 1330, where he was mortally wounded.
His son Ivan Stephen held the throne only until 1331, when the nobility raised up Ivan Alexander, whose Sratsimir house descended from the Shishmanids through the female line; Michael's half-brother Belaur meanwhile kept Vidin as its despot.