The Church of the Holy Apostles was located on the site of the current Fatih Mosque on the Fourth Hill of Constantinople.

A circular mausoleum erected by Constantine I for his own burial was the first building on this site. Next to it a cruciform basilica was built by Constantius II, who deposited in it relics of the apostles Timothy, Luke and Andrew. In 550 the church was rebuilt, again in the shape of a cross, by Justinian I, who added a second mausoleum. The two mausolea served as the burial place of emperors until 1028. After Iconoclasm the church was restored by Basil I and decorated with a cycle of mosaics. The mosaics appear to have been partly redone in the 12th century. After the Turkish conquest the church was ceded to Gennadios II Scholarios as the seat of the patriarchate, but he found it unsuitable and moved instead to the Church of Theotokos Pammakaristos . The church was demolished and the mosque of Mehmed II Fatih built on its site. Several of the imperial sarcophagi were salvaged. The Church of the Holy Apostles resembled that of St. John at Ephesus in its cruciform plan and five-domed elevation, a scheme later replicated at San Marco in Venice.