The siege of Belgrade in 1521 was a notable military campaign conducted by the Ottoman Empire, led by Sultan Suleiman the Magnificent. The fortress of Belgrade was strategically significant, as it controlled key routes along the Danube River and facilitated Ottoman expansion into Central Europe. Prior to the siege, Belgrade had been a contested fortress, changing hands between various European powers, including the Kingdom of Hungary, which was heavily involved in efforts to defend it.

Suleiman, recognizing the city’s importance, initiated a well-coordinated siege involving substantial artillery and skilled military engineers. The Ottomans laid siege to the city beginning in July 1521. The defenders, led by Hungarian commander Mihály Szilágyi, put up fierce resistance, utilizing the city’s strong fortifications. Notable was the use of cannons, a relatively new technology that significantly contributed to the success of the siege. After weeks of relentless assault, the Ottomans breached the walls and stormed the city on August 28, 1521.

The fall of Belgrade marked a turning point in Ottoman expansion into Europe, paving the way for future campaigns in Hungary and beyond. It solidified Suleiman's reputation as a formidable military leader and emphasized the Ottoman Empire's dominance over its European rivals during this period.