It was settled by the Slavs in the 520s, and changed hands several times between the Byzantine Empire, Frankish Empire, Bulgarian Empire and Kingdom of Hungary before it became the capital of Serbian king Stephen Dragutin (1282–1316).In 1521, Belgrade was conquered by the Ottoman Empire and became the seat of the Sanjak of Smederevo.After a prolonged battle which destroyed much of the city, between 6 and 9 October 1915, Belgrade fell to German and Austro-Hungarian troops commanded by Field Marshal August von Mackensen on 9 October 1915.The city was liberated by Serbian and French troops on 1 November 1918, under the command of Marshal Louis Franchet d'Espérey of France and Crown Prince Alexander of Serbia.Chipped stone tools found at Zemun show that the area around Belgrade was inhabited by nomadic foragers in the Palaeolithic and Mesolithic eras.Some of these tools belong to the Mousterian industry, which are associated with Neanderthals rather than modern humans.One of the most important prehistoric cultures of Europe, the Vinča culture, evolved within the Belgrade area in the 6th millennium BC.In antiquity, Thraco-Dacians inhabited the region, and after 279 BC Celts conquered the city, naming it Singidūn.
Lazarević built a castle with a citadel and towers, of which only the Despot's tower and west wall remain.
Aurignacian and Gravettian tools have also been discovered there, indicating occupation between 50,000 and 20,000 years ago.
There are several Starčevo sites in and around Belgrade, including the eponymous site of Starčevo.
Later, Grand vizier Sinan Pasha ordered the relics of Saint Sava to be publicly torched on the Vračar plateau; in the 20th century, the Temple of Saint Sava was built to commemorate this event.
During this period, the city was affected by the two Great Serbian Migrations, in which hundreds of thousands of Serbs, led by two Serbian Patriarchs, retreated together with the Austrians into the Habsburg Empire, settling in today's Vojvodina and Slavonia.