The History of Belgrade Fortress

At the end of the 1st century, due to its strategic importance, the Romans had built a castrum, as a permanent military camp for the 4th Flavius' Legion. After the Goths and Huns destroyed it, the fortification was rebuilt during the first decades the 6th century. About a century later it was newly destroyed by Avars and Slavs.
Alongside the fortress, on the hill that rises over the Sava and the Danube, the ancient Singidunum evolved, and later on, the Slav-built Belgrade. For hundreds of years, the medieval town grew within the fortification, seeking protection inside its rampart. The Belgrade Fortress has been destroyed and rebuilt many times. Rising on the remains of Roman walls are Serbian ramparts and on top of them, Turkish and Austrian fortifications. In the 12th century, Byzantine emperor Manuel I Comnenus build a new fortress on the Roman ruins. In the first decades of the 14th century the small castle on the hill expanded down to the riverbanks. During the reign of Serbian despot Stefan Lazarević, Belgrade, as the new capital of Serbia was strengthened with new fortifications in the Upper and Lower town. In the fortress complex, a new court for the despot was built, and a port for military use was set up on the Sava banks. Inside the walls, a prosperous medieval town developed. From the invasion of the Turks in 1521, to the end of the 17th century no major construction work had been done on the fortress. The war between Austria and Turkey opened a new chapter in Belgrade history. As a key fortification amidst the 18th century conflicts, the Fortress was reconstructed three times. The old castle was torn down, and new fortifications were built atop of most of the medieval walls. During the Austrian occupation (1717 - 1739), when new modern fortifications were built, the Belgrade Fortress represented one of the major military strongholds in Europe. It was constructed according to designs prepared by Swiss-born general Nicolaus Docsato Demorese who was at the service of the Austrian Army. By a twist of fate, in March 1738, the Fortress architect was executed at dawn at the foot of the Belgrade ramparts, because of a military defeat near Niš. Before the Turks re-entered Belgrade in 1740, all new fortification were torn down. By the end of 18th century the fortress acquired its final shape. In the destruction brought about by the wars that followed, nearly all the buildings in Upper and Lower town have been swept away, and the ramparts have also been greatly damaged.