Originally, during the Latin occupation of the 12th century, the mosque was a Catholic Italian church. It was later used as a religious establishment by the Kalenderi sect after the conquest of Istanbul by Sultan Mehmet, the Conqueror.
Babüssaade Aðasý Maktul Beþir Aða converted it into a mosque in the first half of the 18th century. A fire caused extensive damage in the 19th century, and it was renovated in 1854. Lightning struck the minaret in 1930, it was then abandoned.
It was later researched and excavated by Harvard University and Ýstanbul Technical University between 1966-1975. It was restored in 1968 and re-opened for worship.
The walls are a mixture of stone and brick. A large dome spans the ceiling. The inner walls are covered by colored marble and engraved ornamentation.
