The United Principalities emerged when the territories of Moldavia and Wallachia were united under Prince Alexander Ioan Cuza in 1859. In 1866 Prince Karl of Hohenzollern-Sigmaringen was called to the throne as the Ruling Prince of the Romanian Principate and in 1881 he was finally crowned as King Carol I the first monarch of the Kingdom of Romania. Independence from the Ottoman Empire was declared on 9 May 1877, and was internationally recognised the following year. At the end of World War I, Transylvania, Bukovina and Bessarabia united with the Kingdom of Romania.
World War II gave cause to the rise of a military dictatorship in Romania under far-right and antisemitic Marshal Ion Antonescu, who chose to fight on the side of the Axis powers from 1941 to 1944. After his removal, Romania switched sides in 1944 and joined the Allies. By the end of the war, some formerly Romanian northeastern territories were occupied by the Soviet Union, with Red Army units stationed on Romanian soil. In 1947 Romania forcibly became a People's Republic (1947-1965) and a member of the Warsaw Pact. In 1965 Nicolae Ceauşescu became General Secretary of the Romanian Workers' Party, and the harsh austerity measures, political repression, and cult of personality he implemented led to the Socialist Republic of Romania (1965-1989) becoming the most Stalinist police state in the Eastern bloc. Eventually his authoritarian government was toppled in December 1989 during the Romanian Revolution of 1989.
Romania derives from the Latin romanus, meaning "citizen of Rome". The first known use of the appellation was by 16th-century Italian humanists travelling in Transylvania, Moldavia, and Wallachia.