sentences:  On Christmas Eve of 1247 the Knights besieged and overwhelmed a major Pomesanian fortress, which they later renamed Christburg (Dzierzgoń), and newly arrived Henry III, Margrave of Meissen subdued the Pogesanians.Swantopolk retaliated and destroyed Christburg, but the Knights rebuilt it in a new location.Both Prussian and Swantopolk's armies failed to capture the new castle.