The Kingdom of Hungary was a monarchy in Central Europe that existed from the Middle Ages into the twentieth century (1000-1946 with the exception of 1918-1920). The Principality of Hungary emerged as a Christian kingdom upon the coronation of the first king Stephen I at Esztergom in about the year 1000; his family (the Árpád dynasty) led the monarchy for 300 years. By the 12th century, the kingdom became a European middle power within the Western world.
Due to the Ottoman occupation of the central and southern territories of Hungary in the 16th century, the country was partitioned into three parts: the Habsburg Royal Hungary, Ottoman Hungary and the semi-independent Principality of Transylvania. The House of Habsburg held the Hungarian throne after the Battle of Mohács until 1918 and also played a key role in the liberation wars against the Ottoman Empire.
From 1867 territories connected to the Hungarian crown were incorporated into Austria-Hungary under the name of Lands of the Crown of Saint Stephen. The monarchy ended with the deposition of the last king Charles IV in 1918, after which Hungary became a republic. The kingdom was nominally restored during the "Regency" of 1920-46, ending with the Soviet occupation in 1946.
The Kingdom of Hungary was a multiethnic state from its inception until the Treaty of Trianon and it covered what is today Hungary, Poland, Slovakia, Transylvania and other parts of what is now Romania, Carpathian Ruthenia (now part of Ukraine), Vojvodina (now part of Serbia), Burgenland (now part of Austria), and other smaller territories surrounding present-day Hungary's borders. From 1102 it also included Croatia, being in personal union with it, united under the King of Hungary.
Today, the feast day of the first king Stephen I (20 August) is a national holiday in Hungary, commemorating the foundation of the state (Foundation Day).