After the Russo-Turkish War (1877–1878), when German diplomats assigned what were seen as Russian spoils of war to Turkey, the relationship between Russia and the German Empire became complicated. The Russian Empire resumed the construction of fortresses at its western borders for defence against a potential invasion from Germany in the West. On 7 July 1879 the Russian Emperor Alexander II approved a proposal from the Russian military leadership to build the largest "first-class" defensive structure in the entire state – the  Kaunas Fortress. Large numbers of Lithuanians went to the United States in 1867–1868 after a famine.