The ‘Dual Monarchy’, established by the Austrian emperor Francis Joseph after Austria’s defeat by Prussia in 1866 in which Austria and Hungary became autonomous states under a common sovereign. The dualist system came under increasing pressure from the other subject nations, including Croatians, Serbs, Slovaks, Romanians, and Czechs, and failure to resolve these nationalistic aspirations was one of the causes of World War I. After their victory the Allies gave support to the emergent nations, and the Austro‐Hungarian Empire was dissolved by the Versailles peace settlement (1919).

Austria-Hungary. The empire and its successor states. Austria-Hungary was doomed to collapse because of the ethnic tensions between its subject peoples.