The Church of the Holy Apostles was one of the most important buildings in Byzantine Constantinople. The mausolea of Constantine the Great (the main imperial burial place until the eleventh century) and of Justinian I were in the complex surrounding this vast cruciform church. Nothing of this complex appeared to have survived its demolition to clear the site of the Ottoman mosque complex of Fatih Camii after 1461. Fieldwork in 2001 recorded walls pre–dating the fifteenth–century phase of the mosque complex, still standing above ground level and apparently including a large rectilinear structure. This is identified as the Church of the Holy Apostles and an adjacent enclosure may be that containing the mausoleum of Constantine the Great. The reconstructed church plan resembles those of St John of Ephesus and St Mark's (San Marco), Venice – churches known to have been modelled on the Church of the Holy Apostles, Constantinople.