In 1866, Austria lost the war with Prussia and several Italian states. Francis Joseph I was urged to solve the internal problems of his realm and was well-advised to provide a substantial rise to the Hungarian nobility, which had stayed in passive resistance to him after the crushed Hungarian revolution of 1848 and 1849. By the Austro-Hungarian Compromise of 1867 ("Ausgleich"), the Kingdom of Hungary and the Empire of Austria as two separate entities joined together on an equal basis to form the Dual Monarchy of Austria-Hungary. Thus the former Habsburg-ruled lands were restructured into a dual union which shared a monarch and a common army, navy and foreign policy. Transylvania became again the integral part of Hungary while Croatia-Slavonia were acknowledged as part of the Lands of the Crown of Saint Stephen, which were called Transleithania by government officials to distinguish them from Cisleithania, the Austrian part of the Empire from 1867 onwards. The latter were known in the internal administration as the "Kingdoms and Lands Represented in the Imperial Council" ("Die im Reichsrat vertretenen Königreiche und Länder"). Unofficially ever since, these territories officially were called "Austria" from 1915 to 1918 only, despite the fact that all the citizens held the common Austrian citizenship since 1867.