During these centuries the Serbian state (and influence) expanded significantly.
The northern part, Vojvodina, was ruled by the Kingdom of Hungary.
The period known as the Fall of the Serbian Empire saw the once-powerful state fragmented into duchies, culminating in the Battle of Kosovo (1389) against the rising Ottoman Empire.
The Serbian Despotate was finally conquered by the Ottomans in 1459.
The most famous of these was Constantine the Great, the first Christian Emperor, who issued an edict ordering religious tolerance throughout the Empire.
When the Roman Empire was divided in 395, most of Serbia remained under the Eastern Roman Empire, while its northwestern parts were included in the Western Roman Empire.
By the mid-16th century, the entire modern-day Serbia was annexed by the Ottomans, at times interrupted by the Habsburg Empire, which started expanding towards Central Serbia from the end of the 17th century, while maintaining a foothold in modern-day Vojvodina.
Serbia is a member of numerous organizations such as the UN, Co E, OSCE, Pf P, BSEC, and CEFTA. These authors used these names to refer to Serbs and Sorbs in areas where their historical (or current) presence was/is not disputed (notably in the Balkans and Lusatia), but there are also sources that mention same or similar names in other parts of the World (most notably in the Asiatic Sarmatia in the Caucasus). From 1945 to 1963, the official name for Serbia was the People's Republic of Serbia, which became the Socialist Republic of Serbia from 1963 to 1990.
During the Iron Age, Thracians, Dacians, and Illyrians were encountered by the Ancient Greeks during their expansion into the south of modern Serbia in the 4th century BC; the northwesternmost point of Alexander the Great's empire being the town of Kale-Krševica.