Russo-Turkish War: The Russian Empire declares war on the Ottoman Empire.

The Russo-Turkish War (1877–1878) was a conflict between the Ottoman Empire and a coalition led by the Russian Empire which included Romania, Serbia, and Montenegro. Precipitating factors included the Russian goals of recovering territorial losses endured during the Crimean War of 1853–1856, re-establishing itself in the Black Sea and supporting the political movement attempting to free Balkan nations from the Ottoman Empire.