The Mausoleum of Fatima Khatun was built by Sultan Qalawun for his wife Umm al-Salih in 1283-4. The shad al-'ama'ir (superintendent of royal constructions, usually an amir) was the Amir 'Alam al-Din Sanjar al-Shuja'i, whose constructions feature architectural and decorative features unprecedented in Cairene architecture.
The use of squinches filled in with keel-arched stalactite pendentives in the dome's zone of transition was a new development.
Creswell, K.A.C. The Muslim Architecture of Egypt, vol. II. Hacker Art Books, New York, 1978.
Ibrahim, Laila 'Ali. "The Transitional Zones of Domes in Cairene Architecture." Kunst des Orients 10 (1975): 5-23.