 Having secured agreement as to non-involvement by the other Great Powers, on 17 April 1877 Russia declared war upon the Ottoman Empire.The Russians, helped by the Romanian Army under its supreme commander, King Carol I (then Prince of Romania), who sought to obtain Romanian independence from the Ottomans as well, were successful against the Turks and the Russo-Turkish War of 1877–1878 ended with the signing of the preliminary peace Treaty of San Stefano on 19 February (3 March N.S.