From the Wikipedia: Vefa Kilise Mosque (Turkish: Vefa Kilise Camii, meaning "the church mosque of Vefa", to distinguish it from the other kilise camiler of Istanbul: also known as Molla Gürani Camii after the name of his founder) is a former Eastern Orthodox church converted into a mosque by the Ottomans. The church was possibly dedicated to Hagios Theodoros (St. Theodore,in Greek: Ἁγίος Θεοδόρος τά Καρβουνάρια), but this dedication is far from certain. The complex represents one of the most important examples of Comnenian and Palaiologan architecture of Constantinople