By 1678, Frederick William had cleared Swedish Pomerania and occupied most of it, with the exception of Rügen which was held by Denmark–Norway. This was followed by another success against Sweden, when Frederick William cleared Prussia of Swedish forces in what became known as the Great Sleigh Drive. However, when Louis XIV of France concluded the Dutch War by the Nijmegen treaties, he marched his armies east to relieve his Swedish ally, and forced Frederick William to basically return to the "status quo ante bellum" by the Treaty of Saint-Germain-en-Laye (1679). Though the Scanian War resulted only in minor territorial gains, attaching a small strip of the Swedish Pomeranian right bank of the lower Oder to Brandenburg-Prussian Pomerania, the war resulted in a huge gain of prestige for the elector.