The Ayakapı Church was a church located near the Holy Gate (Turkish Ayakapı) on the Sea Walls. The name “Ayakapı” probably derives from the Church of Hagia Theodosia, which has traditionally been identified with the nearby Gül Mosque. However it is also possible that this structure is better identified with Ayakapı Church. Its masonry is similar to Gül Mosque, suggesting it dates to the 11th or 12th century.
It measured approximately 5 X 5 meters and belonged to the atrophied Greek-cross type. There was a narthex projecting beyond the structure to the south. It has been argued that this feature, along with the indication of broken walls on either side of the apse, suggest that this was a parekklesion attached to a larger building. Its ruins are now located under a house and inside a workshop. Its apse can also be seen in a café.
Plan by Schneider
Architecture and Ritual in the Churches of Constantinople: Ninth to Fifteenth Centuries by V. Marinis
Bildlexikon zur Topographie Istanbuls: Byzantion, Konstantinupolis, Istanbul by Wolfgang Müller-Wiener