Carol I (20 April 1839 – 27 September (O.S.) / 10 October (N.S.) 1914), born Prince Karl of Hohenzollern-Sigmaringen was the ruler of Romania from 1866 to 1914. He was elected Ruling Prince (Domnitor) of the Romanian United Principalities on 20 April 1866 after the overthrow of Alexandru Ioan Cuza by a palace coup. After the defeat of the Ottoman Empire (1878) in the Russo-Turkish War, he declared Romania a sovereign nation (the country had been under the nominal suzerainty of the Ottoman Empire until then). He was proclaimed  King of Romania on . He was the first ruler of the Hohenzollern-Sigmaringen dynasty, which ruled the country until the proclamation of a republic in 1947.