German Crusades
The history of Latvia between 1150 and 1206
At the end of the 12th century, Latvia was more often visited by traders from Western Europe who set out on trading journeys along Latvia's longest river, the Daugava, to Russia. At the very end of the 12th century, German traders arrived and with them came preachers of the Christian faith who attempted to convert the pagan Baltic and Finno-Ugric tribes to the Christian faith. The Livs did not willingly convert to the new and different beliefs and practices, and particularly opposed the ritual of baptism. News of this reached the Pope in Rome and it was decided that Crusaders would be sent into Latvia to influence the situation.
The Germans founded Riga in 1201, and gradually it became the largest city in the Southern part of the Baltic Sea. Order of the Sword Brothers was founded in 1202 to subjugate the local people. The Livs were conquered by 1207 and the most of Latgalians by 1214.
References: Wikipedia