What Day Was the fall of Constantinople?

About this date

Ottoman forces under Sultan Mehmed II captured Constantinople after a roughly seven-week siege, ending the more than thousand-year-old Byzantine Empire and the reign of its final emperor, Constantine XI, who died in the city's defense.

Historians commonly cite this event as marking the symbolic end of the Middle Ages in European historiography, though like most such period boundaries it's a convention rather than a precise line.

This date predates the Gregorian calendar's 1582 introduction, so it's recorded historically in the older Julian calendar; converting it to a modern Gregorian weekday involves a proleptic (backward-projected) calendar calculation rather than the calendar contemporaries themselves would have used.

The city's massive Theodosian land walls had withstood numerous previous sieges over more than a thousand years, and their eventual breach relied partly on the Ottomans' use of massive cannon, an early example of gunpowder artillery reshaping siege warfare.