The war was characterized by a back-and-forth movement of the Swedish and Prussian armies, neither of whom would score a decisive victory. It started when Swedish forces advanced into Prussian territory in 1757, but were repelled and blockaded at Stralsund until their relief by a Russian force in 1758. In the course of the following, renewed Swedish incursion into Prussian territory, the small Prussian fleet was destroyed and areas as far south as Neuruppin were occupied, yet the campaign was aborted in late 1759 when the undersupplied Swedish forces succeeded neither in taking the major Prussian fortress of Stettin (now Szczecin) nor in combining with their Russian allies.