Austria-Hungary (; ), also known by other names and often referred to as the Austro-Hungarian Empire in English-language sources, was a constitutional union of the Empire of Austria (The Kingdoms and Lands Represented in the Imperial Council or Cisleithania) and the Kingdom of Hungary (Lands of the Crown of Saint Stephen or Transleithania) that existed from 1867 to 1918, when it collapsed as a result of defeat in World War I. The union was a result of the Compromise of 1867 and came into existence on 30 March 1867, when the compromise was ratified by the Hungarian parliament. Austria-Hungary consisted of two monarchies (Austria and Hungary), and one autonomous region: Croatia–Slavonia under the Hungarian crown, which negotiated its own compromise (Nagodba) with Hungary, in 1868. It was ruled by the House of Habsburg, and constituted the last phase in the constitutional evolution of the Habsburg Monarchy. Following the 1867 reforms, the Austrian and the Hungarian states were co-equal. The Compromise required regular renewal, as did the customs union between the two components of the union. Foreign affairs and the military came under joint oversight, but all other governmental faculties were divided between respective states.