Ahmad ibn Fadlan
They were assimilated into the Khazars and Bulgars confederations. The tribe Suwāz in Volga Bulgaria is related to the city Suwār in the same state, and North Caucasian kingdom Suwār. However, it is uncertain whether these Suwār i.e. Sawâr are the Sabirs who gone to the North Caucasus and after 558 retreated to the Volga, came there as the result of the Khazar state creation, or were tribes who never went to the North Caucasus, but stopped on the Volga. Ahmad ibn Fadlan recorded that in the 10th century they still had own leader with the title "Wirgh" (*"Vuyrigh", Turkic "Buyruq"), and there were some Suwār-Bulghar hostilities.