ing it under Austro-Hungarian occupation. From 1815 to 1903, Principality of Serbia was ruled by the House of Obrenović, except from 1842 to 1858, when it was led by Prince Aleksandar Karađorđević. In 1882, Serbia became a kingdom, ruled by King Milan. In 1903, following May Overthrow, the House of Karađorđević, descendants of the revolutionary leader Karađorđe Petrović assumed power. The 1848 revolution in Austria lead to the establishment of the autonomous territory of Serbian Vojvodina. By 1849, the region was transformed into the Voivodeship of Serbia and Banat of Temeschwar.
World War I and creation of Yugoslavia
In the course of the First Balkan War in 1912, the Balkan League, defeated the Ottoman Empire and conquered its European territories, which enabled territorial expansion into Raška and Kosovo. The Second Balkan War soon ensued when Bulgaria turned on its former allies, but was defeated, resulting Treaty of Bucharest. In two years, Serbia enlarged its territory by 80% and its population by 50%; it also suffered high casualties on the eve of World War I, with around 20,000 dead.
On 28 June 1914 the assassination of Archduke Franz Ferdinand of Austria in Sarajevo by Gavrilo Princip, a member of the Young Bosnia organization, led to Austria-Hungary declaring war on Serbia. In defense of its ally Serbia, Russia mobilized its troops, which resulted in Austria-Hungary's ally Germany declaring war on Russia. The retaliation by Austria-Hungary against Serbia activated a series of military alliances that set off a chain reaction of war declarations across the continent, leading to the outbreak of World War I within a month. Serbia won the first major battles of World War I, including the Battle of Cer and Battle of Kolubara – marking the first Allied victories against the Central Powers in World War I. Despite initial success, it was eventually overpowered by the Central Powers in 1915. Most of its army and some people
