Today’s Kalyan Mosque was built at the beginning of the 16th century in the time of the first Shaybanids. Since that time, except for Soviet period it served as the cathedral mosque of Bukhara. The mosque replaced the old Qarakhanid cathedral mosque of the 12th century which was built simultaneously with Kalyan Minaret. This Shaybanid mosque is comparable with Temurid cathedral mosques in Samarkand and Herat. It is behind Bibi-Khanym Mosque in Samarkand by number of structures, but its area which is 130×80 sq. meter surpasses the last one. Kalyan Mosque is traditionally rectangular and has four aivans. Entrance aivan has an external portal facing Poi-Kalyan Square and internal portal turned tu the yard. Arched galleries with 288 domes based on 208 columns surround the yard. An octahedral stand used as lectern is situated on the central axis at the internal portal. Mosaics and glazed bricks make colored decoration of facades.