The principalities of Wallachia and Moldavia - for centuries under the suzerainty of the Turkish Ottoman Empire - secured their autonomy in 1856; they were de facto linked in 1859 and formally united in 1862 under the new name of Romania. The country gained recognition of its independence in 1878. It joined the Allied Powers in World War I and acquired new territories - most notably Transylvania - following the conflict. In 1940, Romania allied with the Axis powers and participated in the 1941 German invasion of the USSR. Three years later, overrun by the Soviets, Romania signed an armistice. The post-war Soviet occupation led to the formation of a communist "people's republic" in 1947 and the abdication of the king. The decades-long rule of dictator Nicolae CEAUSESCU, who took power in 1965, and his Securitate police state became increasingly oppressive and draconian through the 1980s. CEAUSESCU was overthrown and executed in late 1989. Former communists dominated the government until 1996 when they were swept from power. Romania joined NATO in 2004 and the EU in 2007.