The Austrian Empire was a Central-Eastern European multinational great power from 1804 to 1867, created by proclamation out of the realms of the Habsburgs. During its existence, it was the third most populous empire in Europe after the Russian Empire and the United Kingdom. Along with Prussia, it was one of the two major powers of the German Confederation. Geographically, it was the third-largest empire in Europe after the Russian Empire and the First French Empire. Proclaimed in response to the First French Empire, it partially overlapped with the Holy Roman Empire until the latter's dissolution in 1806.
The Kingdom of Hungary—as Regnum Independens—was administered by its own institutions separately from the rest of the empire. After Austria was defeated in the Austro-Prussian War of 1866, the Austro-Hungarian Compromise of 1867 was adopted, joining the Kingdom of Hungary and the Empire of Austria to form Austria-Hungary.