Austria-Hungary, often referred to as the Austro-Hungarian Empire or the Dual Monarchy, was a constitutional monarchy and great power in Central Europe between 1867 and 1918. It was formed with the Austro-Hungarian Compromise of 1867 and was dissolved following its defeat in the First World War.
At its core was the dual monarchy which was a real union between the Austrian Empire and the Kingdom of Hungary. A third component of the union was the Kingdom of Croatia-Slavonia, an autonomous region under the Hungarian crown, which negotiated the Croatian–Hungarian Settlement in 1868. From 1878 Austria-Hungary jointly governed Bosnia-Herzegovina, which it annexed in 1908. Austria-Hungary was ruled by the House of Habsburg and constituted the last phase in the constitutional evolution of the Habsburg Monarchy. The union was established by the Austro-Hungarian Compromise on 30 March 1867 in the aftermath of the Austro-Prussian War. Following the 1867 reforms, the Austrian and Hungarian states were co-equal in power. The two states conducted common foreign, defense, and financial policies, but all other governmental faculties were divided among respective states.