The Kok-Gumbaz, or Blue Dome Mosque, was built in 1437 by Ulugh Beg, the Timurid ruler and celebrated astronomer, as a Friday prayer mosque in honour of his father Shah Rukh. The name is literal: the central dome is clad in the deep blue tilework that defines Timurid architecture across Central Asia.
The mosque is still in active use, which gives it a different atmosphere from the archaeological monuments nearby. Friday prayers draw local worshippers; at other times it is open to visitors. The interior is spacious and cool, with good surviving tilework and wooden screens.
Directly behind the mosque is the "House of Meditation," a mausoleum built in 1438. Together they form a compact religious ensemble that shows a functioning side of Timurid Shakhrisabz, distinct from the ruined grandeur of the Ak-Saray.