Ibn Fadlan

"Khazar is the name of a region whose chief city is called Itil. Itil is also the name of a river that flows to Khazar from the Rus and Bulghars. Itil is a city while Khazar is the name of a kingdom and not the name of a city. There are two parts to Itil; on the west side of the river it is called Itil, which is the larger part. On the east side lives the king, who in their language is called Ilek, and he is also called Bak (Beg). The western part in size is about a farsakh in length and around it is a wall. There are no buildings for their houses are tents of felt, except for a few structures built of clay; they do have bazaars and baths. In the town are many Muslims. It is said that there are more than ten thousand and they have about thirty mosques."