Pannonia was a province of the Roman Empire bounded on the north and east by the Danube, coterminous westward with Noricum and upper Italy, and southward with Dalmatia and upper Moesia. Pannonia was located in the territory that is now western Hungary, western Slovakia, eastern Austria, northern Croatia, north-western Serbia, northern Slovenia, and northern Bosnia and Herzegovina.

Serbia, officially the Republic of Serbia, is a landlocked country at the crossroads of Southeast and Central Europe, located in the Balkans and the Pannonian Plain. It borders Hungary to the north, Romania to the northeast, Bulgaria to the southeast, North Macedonia to the south, Croatia and Bosnia and Herzegovina to the west, and Montenegro to the southwest. Serbia claims a border with Albania through the disputed territory of Kosovo. Serbia has about 6.6 million inhabitants, excluding Kosovo. Its capital Belgrade is also the largest city.