Khanate of Kazan
In the 1430s, the region became independent as the base of the Khanate of Kazan, a capital having been established in Kazan, 170 km up the Volga from the ruined capital of the Bulgars. The Khanate of Kazan was conquered by the troops of Tsar Ivan IV the Terrible in the 1550s, with Kazan being taken in 1552. Some Tatars were forcibly converted to Christianity and cathedrals were built in Kazan; by 1593, mosques in the area were destroyed. The Russian government forbade the construction of mosques, a prohibition that was not lifted until the 18th century by Catherine II.