The modern religious history of Central Asia is dominated by two imperial projects with opposite intentions and comparable effects on institutions.
Russian expansion brought most of the region under tsarist rule in the nineteenth century. The policy toward Islam was not straightforwardly hostile: Robert Crews has argued that the empire deliberately used Islamic institutions as instruments of government, appointing and funding muftis, giving state backing to religious courts, and thereby making itself an arbiter in Muslim disputes. Believers learned to appeal to the tsar's officials against their own clergy, which entangled the state in doctrinal questions it had no interest in.
Soviet policy after the 1920s was to end religion altogether. Mosques and madrasas were closed in enormous numbers, endowments confiscated, Arabic script replaced first by Latin and then by Cyrillic, cutting a generation off from the written tradition, the pilgrimage and the fast discouraged or banned, and clergy imprisoned or killed. A single officially recognised board was left to administer what remained. Popular practice continued around shrines and lineages, which is what survived best.
Since independence in 1991 the five republics have rebuilt mosques and reopened institutions while regulating religion tightly, registering congregations, restricting foreign missionary activity and treating unauthorised religious organisation as a security matter. Nomadic and shamanic traditions have also re-emerged, and Tengrism has been promoted in several places as a pre-Islamic national heritage.