The Church of the Holy Apostles was first built in the fourth century, in a cruciform shape and attached to the round mausoleum of Constantine on the highest hill of the newly founded city. In the time of Justinian I the church was rebuilt completely on a larger scale, leaving Constantine's mausoleum intact and adding a second cruciform mausoleum. Most emperors and their wifes were buried there until the 11th century. The church of the Holy Apostles had at least the same overall size as the Hagia Sophia; was erected on the groundplan of a greek cross, had one dome with windows over the centre and four domes without on the cross arms. However, the details of construction are much disputed, since no part of the building survives and the later copies in the west like San Marco in Venice or Saint-Front in Périgeux seem to imitate the original building quite freely. The church was given to the greek patriarch after the Ottoman conquest in 1453, but then demolished in 1456 and subsequently replaced by the big Mosque of Mehmet Fatih.