The Lithuanian Crusade was a series of campaigns by the Teutonic Order and the Livonian Order under the pretext of forcibly Christianizing the pagan Grand Duchy of Lithuania. The Livonian Order occupied Riga in 1202 and in the 1230s they settled in Chełmno Land, a fief of Poland. They first conquered other neighboring Baltic tribes—Curonians, Semigallians, Latgalians, Selonians, and Old Prussians—in the Livonian Crusade and Prussian Crusade.

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, which by 1440, became the largest European state controlling an area from the Baltic Sea in the north to the Black Sea in the south.