Church of Christ Pantocrator ( Zeyrek Camii ), Istanbul.

This building consists of three seperately-built structures. The Monastery of Christ Pantocrator, 'the Almighty', was founded by Empress Irene, wife of John II Comnenus, some time after 1118, its church seen here on the right ( south ). Some time later John built a smaller church to the north dedicated to the Virgin Eleousa, 'the Merciful'. Finally by 1136, the two churches were joined by a funerary chapel built between them whose crypt served as the imperial mausoleum. Converted into a mosque after the Ottoman Conquest.
View of the west elevation from Fazilet Sokağı.
... The structure has undergone restoration.