Lands of the Crown of Saint Stephen in the context of "Diet of Hungary"

The Kingdom of Yugoslavia was a country in Southeast and Central Europe that existed from 1918 until 1941. From 1918 to 1929, it was officially called the Kingdom of Serbs, Croats, and Slovenes, but the term "Yugoslavia" (lit. 'Land of the South Slavs') has been its colloquial name as early as 1922 due to its origins. The official name of the state was changed to "Kingdom of Yugoslavia" by King Alexander I on 3 October 1929.

The preliminary kingdom was formed in 1918 by the merger of the provisional State of Slovenes, Croats and Serbs (itself formed from territories of the former Austro-Hungarian Empire, encompassing what is now Bosnia and Herzegovina and most of what are now the states of Croatia and Slovenia) and Banat, Bačka and Baranja (that had been part of the Kingdom of Hungary within Austria-Hungary) with the formerly independent Kingdom of Serbia. In the same year, the Kingdom of Montenegro also proclaimed its unification with Serbia, whereas the regions of Kosovo and what is today North Macedonia had become parts of Serbia prior to the unification.

The Triune Kingdom (Croatian: Trojedna kraljevina) or Triune Kingdom of Croatia, Slavonia and Dalmatia (Croatian: Trojedna Kraljevina Hrvatske, Slavonije i Dalmacije) was the concept—advocated by the leaders of the 19th-century Croatian national revival—of a united kingdom between Croatia, Slavonia and Dalmatia, which were already within the Austrian Empire under one king, who was also the Emperor of Austria, but were politically and administratively separate entities. This concept had roots in the high medieval period, as a successor to the historical Kingdom of Croatia which was made up of those regions.

After 1867, Croatia and Slavonia were within the Hungarian half of Austria-Hungary and were united in 1868 as the Kingdom of Croatia-Slavonia, where the name Triune Kingdom of Croatia, Slavonia and Dalmatia became official. However, Dalmatia, being located in the Austrian half, still remained de facto separate. Until the end of the Austro-Hungarian Empire, several Croatian political parties and groups sought recognition of the Triune Kingdom and the incorporation of Dalmatia into Croatia-Slavonia. The Croatian intelligentsia, especially lawyers and historians, played a key role in interpreting historical sources so as to legitimize the demand for the Triune Kingdom.

The Lands of the Hungarian Crown (Hungarian: A Magyar Szent Korona Országai) was the titular expression of Hungarian pretensions to the various territories that the king of Hungary ruled nominally or absolutely.

They are distinct from the Lands of the Crown of Saint Stephen, which referred to a constituent part of the territory of Austria-Hungary following the Austro-Hungarian Compromise of 1867 up until the dissolution of the empire in 1918 at the end of World War I.

Cisleithania, officially The Kingdoms and Lands Represented in the Imperial Council (German: Die im Reichsrat vertretenen Königreiche und Länder), was the northern and western part of Austria-Hungary, the Dual Monarchy created in the Compromise of 1867—as distinguished from Transleithania (i.e., the Hungarian Lands of the Crown of Saint Stephen east of ["beyond"] the Leitha River). This name for the region was a common, but unofficial one.