KA'USIYEH DYNASTY

(AD 665c. 1006), branch of the Bavand dynasty, which ruled in Tabaristan (now Mazandaran, northern Iran). The origins and early history of the Ka'usiyeh branch are obscure. Its founder and the founder of the main dynasty was a certain Bav (ruled 665680). The dynasty was centred at Ferim, in the mountainous country southwest of Sari. Its geographical isolation and the difficult nature of the terrain enabled it to survive. In c. 854 Qaren I (ruled 837867) converted to Islam. During the 10th century the Bavands maintained their independence through various marriage alliances with the Buyid and Zeyarid dynasties. Rostam III (ruled 100657) became a vassal of the Zeyarid king Qabus, but with weakening of Zeyarid power, Rostam and his successor Qaren II (ruled 105774) reigned as petty rulers in the mountainous area near Sari. The Ka'usiyeh branch was succeeded c. 1074 by another branch of the Bavand dynasty known as Espahbadiyeh, which ruled in Mazandaran and Gilan until 1210.