The first years of the uprising were successful for the Prussians, but the Knights received reinforcements from Western Europe and were gaining the upper-hand in the conflict. The Prussians launched raids against the Chełmno Land, where the Knights first established themselves in late 1220s. The apparent aim of these raids were to force the Knights to devote as many troops in defense of Chełmno as possible so that they could not organize raids deep into Prussian territory. As other clans became preoccupied fending off Teutonic attacks from their forts, only Diwanus and his Bartians were able to continue the war in the west. They made several minor expeditions to Chełmno Land each year. The major Prussian offensive was organized in 1271 together with Linka, leader of the Pogesanians. The Bartian infantry and Pogesanians besieged a border castle, but were fended off by the Knights from Christburg. The Prussians who managed to escape joined their cavalry while the Knights set up a camp on the opposite bank of the Dzierzgoń River, blocking the route home.