With a population of around 21 million, Romania is one of the largest countries in Central and Eastern Europe. Between 1250 and 1350, the independent Romanian principalities of Wallachia and Moldavia emerged. In the 15th and 16th centuries Ottoman Turks conquered the principalities. In 1859 Wallachia and Moldavia were united as Romania. The country gained independence in 1878, and was proclaimed a kingdom in 1881. It joined the Allied Powers in World War I and acquired new territories - most notably Transylvania – after the war. Romania entered World War II on the side of the Axis Powers in 1941, but after Soviet troops entered Romania in 1944 it joined the Allies. The post-war Soviet occupation led to the establishment of a Communist government, and in 1947 the king was forced to abdicate. Nicolae Ceausescu’s 24 years of harsh, repressive leadership was ended in late 1989 when he was overthrown and executed. However, former Communists dominated the government until 1996 when they were swept from power. Romania joined NATO in 2004 and the European Union in 2007. Romania is endowed with substantial natural resources including rich agricultural lands, diverse energy resources such as coal, oil, and natural gas, and an industrial base encompassing a wide range of manufacturing activities.