Istanbul, a cosmopolitan city, was besieged 28 times throughout history before its conquest in 1453 by Ottoman Sultan Mehmed II.

Mehmed II entered the city in the afternoon on the first day of the conquest. He went to Hagia Sophia – now a mosque – and prayed there, saying: "My throne is Istanbul from now on.”

Constantinople was conquered after a siege that lasted for 54 days with intervals.

The conquest ended the 1,058-year-old Byzantine Empire, brought the Middle Ages to a close and made Istanbul the proud new capital of the Ottoman Empire.