Sultan Mehmed II's attacking forces outnumbered the city's 10,000 defenders by at least 10 to one. The siege lasted for fifty days and was hard-fought at every stage. The Ottoman Turks breached the city walls using heavy artillery, then fought their way into the city in hand-to-hand battles.
As ruler, Mehmed renamed the city Istanbul. He demolished the Church of the Holy Apostles, the burial place of the Byzantine emperors including Constantine himself, and replaced it with his own tomb.