Siege of Belgrade
1440 CE.
Shown on the map at 44.490°, 10.280°.
The siege of Belgrade was a long siege by the forces of the Ottoman Empire, lasted about six or seven months in 1440. Belgrade was an important fortified town of the Serbian Despotate and the key fortress of the Hungarian defense line after the Ottoman subjugation of Serbia in 1439. The siege ended with a dramatic final assault, the Ottomans were repelled, and after the failed assault the Turks gave up the siege and returned home.
Text from the Wikipedia article Siege of Belgrade (1440), licensed CC BY-SA 4.0.