Kingdom of Croatia-Slavonia

The Kingdom of Croatia-Slavonia (Croatian: Kraljevina Hrvatska i Slavonija; Hungarian: Horvát-Szlavónország or Horvát–Szlavón Királyság; Austrian German: Königreich Kroatien und Slawonien) was a nominally autonomous kingdom and constitutionally defined separate political nation within the Austro-Hungarian Empire. It was created in 1868 by merging the kingdoms of Croatia and Slavonia following the Croatian–Hungarian Settlement of 1868. It was associated with the Kingdom of Hungary within the dual Austro-Hungarian state, being within the Lands of the Crown of St. Stephen, also known as Transleithania. While Croatia had been granted a wide internal autonomy with "national features", in reality, Croatian control over key issues such as tax and military issues was minimal and hampered by Hungary. It was internally officially referred to as the Triune Kingdom of Croatia, Slavonia and Dalmatia, also simply known as the Triune Kingdom, and had claims on Dalmatia, which was administered separately by the Austrian Cisleithania. The city of Rijeka, following a disputed section in the 1868 Settlement known as the Rijeka Addendum, became a corpus separatum and was legally owned by Hungary, but administered by both Croatia and Hungary.

The Kingdom of Croatia-Slavonia was ruled by the emperor of Austria, who bore the title King of Croatia, Slavonia and Dalmatia and was confirmed by the State Sabor (Parliament of Croatia-Slavonia or Croatian-Slavonian Diet) upon accession. The King's appointed steward was the Ban of Croatia and Slavonia. On 21 October 1918, Emperor Karl I, known as King Karlo IV in Croatia, issued a Trialist manifest, which was ratified by the Hungarian side on the next day and which unified all Croatian Crown Lands. One week later, on 29 October 1918, the Croatian State Sabor proclaimed an independent kingdom which entered the State of Slovenes, Croats and Serbs.