On 29 May 1453, the forces of Mehmed II captured Constantinople. The fall ended Byzantine imperial government in the city. It also began a longer process in which the Ottoman dynasty rebuilt and repopulated the capital it had just taken.
Controlling access before the siege
Constantinople could receive supplies by sea, and that shaped Ottoman preparations. The fortress of Rumeli Hisarı, built in 1452, strengthened Mehmed’s position on the Bosporus. Inside the city, Constantine XI’s defenders relied on the land walls and sought to keep maritime routes open wherever possible.
A siege on land and water
Artillery damaged the land defences, but the defenders repeatedly repaired breaches and fought to hold them. A chain across the mouth of the Golden Horn kept Ottoman ships from sailing straight into the harbour. Moving some vessels overland into the inlet forced the defenders to account for another front. The final assault came after weeks of pressure on both land and sea.
The aftermath of 29 May
Mehmed turned the captured city into the centre of Ottoman government. The work of forming a capital involved settlement, new institutions and construction as well as the reuse of existing buildings. Istanbul’s historic districts still bring Byzantine and Ottoman structures into the same streetscape.
Why the date matters
The date fixes the military and political turning point. The transformation of streets, institutions and neighbourhoods took much longer. Reading the siege alongside the history of the city helps explain why 1453 matters beyond the outcome of a single campaign.