Montenegro is a country in the Balkans, located along the Adriatic Sea and to the south of Bosnia and Herzegovina, west of Serbia, and north of Albania. Podgorica is its capital and largest city, while Cetinje was the historical capital of the country. During the Middle Ages, Montenegro was divided into Serbian principalities, and the independent Montenegrin state of Duklja was established in 1042 after Stefan Vojislav rebelled against the Byzantine Empire. The region passed through the control off several powers, and the Prince-Bishopric of Montenegro was established in 1696 as a vassal of the Ottoman Empire. In 1852, the Prince-Bishopric became a principality, and the principality became the Kingdom of Montenegro in 1910. The short-lived kingdom made minor territorial acquisitions from the Ottomans during the First Balkan War in 1912, splitting the Sanzak border region with Serbia. From 1916 to 1918, Austria-Hungary occupied Montenegro due to its support for Serbia during World War I, and the government of Montenegro was still in exile when the Podgorica Assembly proclaimed unification with Serbia to form the Kingdom of Yugoslavia.