### Nándorfehérvár (Belgrade, today Beograd, the capital of Serbia)
One of the key factors in the border defence system of the medieval Hungarian kingdom. King Zsigmond of Luxemburg (1387-1437) won this region in 1427 from the Serbian despot in accordance with the treaty of Tata signed in the previous year. The fortress at the confluence of the rivers Danube and Sava was finally occupied by Sultan Suleyman I during his first Hungarian campaign. The fortress was reoccupied by Christian troops only in 1688, more then 150 years later. PG