In 1211 the region was given to the Teutonic Knights by King Andrew II of Hungary in return for guarding the southeastern border of the Kingdom of Hungary against the Cumans. While the king retained his right to mint currency and claims on gold or silver deposits that would be uncovered, he granted the Teutonic Order the right to establish markets and administer justice. The crusaders were also free from taxes and tolls. The Teutonic Knights began building wood-and-earth forts in the area and they had constructed five castles ("quinque castra fortia"): Marienburg, Schwarzenburg, Rosenau, Kreuzburg, and Kronstadt, some of which were made of stone. The military order was successful in reducing the threat of the nomadic Cumans. Medieval Saxons from the Holy Roman Empire developed farms and villages nearby to support the forts and settle the land. The territory was already populated at the time when was disputed. Some medieval sources indicate it was uninhabited, a view challenged by some scholars invoking archaeological and documentary evidence. Bountiful agricultural yields led to further colonization by German immigrants.