Austria-Hungary, also referred to as the Austro-Hungarian Empire and officially as the Austro-Hungarian Monarchy, was a multi-national constitutional dual empire in Central Europe between 1867 and 1918. A military and diplomatic alliance, it consisted of two sovereign states with a single monarch who was titled both the Emperor of Austria and the Apostolic King of Hungary. Austria-Hungary constituted the last phase in the constitutional evolution of the Habsburg monarchy: it was formed with the Austro-Hungarian Compromise of 1867 in the aftermath of the Austro-Prussian War, following wars of independence by Hungary in opposition to Habsburg rule. It was dissolved shortly after Hungary terminated the union with Austria in 1918 at the end of World War I.