country following the Russo-Turkish War in 1878. Serbia remained a principality or kneževina (knjaževina), until 1882 when it became a Kingdom, during which the internal politics revolved largely around dynastic rivalry between the Obrenović and Karađorđević families. In 1885, Serbia protested against the unification of Bulgaria and Eastern Rumelia. The Serbian king, Milan Obrenovic´ (1854–1901), who needed to divert attention away from his domestic problems, demanded that Bulgaria cede some of its territory to Serbia. The Great Powers discouraged him, but he declared war on Bulgaria on November 13, 1885. The Serbo-Bulgarian War ended on March 3, 1886. The Serbian army crossed the lightly defended northwest border of Bulgaria aiming to seize Sofia, the Bulgarian capital. The Bulgarian defenders defeated the invaders and then invaded Serbia. Vienna brokered a peace that restored the old status quo. Serbian casualties totaled 6,800, about triple the 2,300 Bulgarian total. The defeat forced Obrenovic to abdicate in March 1889, and the Serbian crown passed to a regency in the name of his son Alexander (1876–1903). Serbian strategic goals Serbia had multiple national goals. Serbian intellectuals dreamed of a South Slavic state—which in the 1920s became Yugoslavia. The large number of Serbs living in Bosnia looked to Serbia as the focus of their nationalism, but they were ruled by the Germans of the Austrian Empire. Austria's annexation of Bosnia in 1908 deeply alienated the Serbian peoples. Plotters swore revenge, which they achieved in 1914 by assassination of the Austrian heir. Serbia was landlocked, and strongly felt the need for access to the Mediterranean, preferably through the Adriatic Sea. Austria worked hard to block Serbian access to the sea, for example by helping with the creation of Albania in 1912. Montenegro, Serbia's main ally, did have a small port, but Austrian territory intervened, blocking access until Serbia acquired Novi Pazar and part of Macedonia from the Ottoman Empire in 1913. To the south, Bulgaria blocked Serbian access to the Aegean Sea. Serbia, Greece, Montenegro and Bulgaria formed the Balkan League and went to war with the Ottomans in 1912–1913. They won decisively and expelled that Empire from almost all of the Balkans. The main remaining foe was Austria, which strongly rejected Pan-Slavism and Serbian nationalism and was ready to make war to end those threats. Ethnic nationalism would doom the multicultural Austro-Hungarian Empire. Expansion of Serbia would block Austrian and German aspirations for direct rail connections