 Complete the following phrase:  Islam in Central Asia has existed since the beginning of Islamic history. Sunni Islam is the most widely practiced religion in Central Asia. Shiism of Imami and Ismaili denominations predominating in the Pamir plateau and the western Tian Shan mountains almost exclusively Ismailis, while boasting to a large minority population in the Zarafshan river valley, from Samarkand to Bukhara almost exclusively Imamis. Islam came to Central Asia in the early part of the 8th century as part of the 