The Teutonic Knights began to direct their campaigns against pagan Lithuania (see Lithuanian mythology), due to the long existing conflicts in the region (including constant incursions into the Holy Roman Empire's territory by pagan raiding parties) and the lack of a proper area of operation for the Knights, after the fall of the Kingdom of Jerusalem at Acre in 1291 and their later expulsion from Hungary. At first the knights moved their headquarters to Venice, from which they planned the recovery of Outremer, this plan was, however, shortly abandoned, and the Order later moved its headquarters to Marienburg, so it could better focus its efforts on the region of Prussia. Because "Lithuania Propria" remained non-Christian until the end of the 14th century, much later than the rest of eastern Europe, the conflicts stretched out for a longer time, and many Knights from western European countries, such as England and France, journeyed to Prussia to participate in the seasonal campaigns ("reyse") against the Grand Duchy of Lithuania. In 1348, the Order won a great victory over the Lithuanians in the Battle of Strėva, severely weakening them. The Teutonic Knights won a decisive victory over Lithuania in the Battle of Rudau in 1370.