The Kingdom of Hungary was a monarchy in Central Europe that existed from the Middle Ages into the twentieth century (1000–1918, 1920–1946). The Principality of Hungary emerged as a Christian kingdom upon the coronation of the first king Stephen I at Esztergom in 1000 or 1001; 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 in the 16th century, the monarchy split into three parts: the Habsburg Royal Hungary, Ottoman Hungary and the semi-independent Principality of Transylvania. The Habsburg dynasty held the Hungarian throne after the Battle of Mohács 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 1920–1946, ending with the Soviet occupation in 1946.
The Kingdom of Hungary was a multiethnic state before the Treaty of Trianon and it covered what is today Hungary, 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 (except Istria), 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)