The Grand Duchy of Lithuania defeats the Livonian Order in the Battle of Karuse.

The Grand Duchy of Lithuania was a sovereign state in northeastern Europe that existed from the 13th century, succeeding the Kingdom of Lithuania, to the late 18th century, when the territory was suppressed during the 1795 partitions of Poland–Lithuania. The state was founded by Lithuanians, who were at the time a polytheistic nation of several united Baltic tribes from Aukštaitija. By 1440 the grand duchy had become the largest European state, controlling an area from the Baltic Sea in the north to the Black Sea in the south.

The Livonian Order was an autonomous branch of the Teutonic Order, formed in 1237. From 1435 to 1561 it was a member of the Livonian Confederation.

The Battle of Karuse or Battle on the Ice was fought on 16 February 1270 between the Grand Duchy of Lithuania and the Livonian Order on the frozen Baltic Sea between the island of Muhu and the mainland. The Lithuanians achieved a decisive victory. The battle, named after the village of Karuse, was the fifth-largest defeat of the Livonian or Teutonic Orders in the 13th century. Almost all that is known about the battle comes from the Livonian Rhymed Chronicle, which devoted 192 lines to the battle.