The Zeyrek Church-Mosque (Pantakrator Monastery Church), located on Ibadethane Street in the Fatih district of Istanbul, had been the leading church of one of the most important Pantokrator monastery complex during the Byzantine era. The complex was formed by three churches. The church, completed in 1136, during the reign of loannes Kommnenos the II and his first wife Eirene (1118 - 1143), and was dedicated to Jesus Christ.
The monastery was converted to Catholicism during the Crusades. The subsidiary buildings were converted into theological schools by Sultan Mehmet II., the Conqueror. The church, on the other hand, became a mosque. The mosque was named after its first preacher, Molla Zeyrek Mehmet Efendi. The mosque underwent an extensive restoration in the 18th Century but was abandoned later on. The second extensive restoration was carried out in 1966. Today, the mosque is derelict once again and in urgent need of restoration. The construction consists in fact of three seperate buildings lying next to each other, but looks as if it is a single construction. Five domes cover the building. A minarette rises with a single balcony. The floor decorations, excavated during the last restoration are of extraordinary beauty.