On 18 June (OS) or 28 June (NS) the armies met in the Battle of Fehrbellin  The Fehrbellin affair was a mere skirmish, with actual casualties amounting to fewer than 600 men—but it was a defeat by a numerically inferior force from a territory Sweden had little regard for. As a result of this defeat, Sweden appeared vulnerable, encouraging neighbouring countries that had suffered invasion by Sweden in the prior Swedish campaigns to join in the Scanian War. Wrangel retreated to Swedish Demmin. When the United Provinces initially asked for Danish support against the French and their allies in the Franco-Dutch War, Danish-Norwegian King Christian V wanted to join them, and go to war with Sweden immediately to recapture the historically Danish provinces of Scania and Halland. Count Peder Griffenfeld, an influential royal adviser, advised against it, and instead advocated a more pro-France policy. But when the numerically superior Swedes lost the Battle of Fehrbellin on June 28, 1675, it was the first such defeat of Swedish forces since the Thirty Years' War. Christian V saw his chance, and overcoming Griffenfeld's opposition, attacked. The second largest Swedish garrison in North Germany, after Swedish Pomerania, was the twin Duchy of Bremen-Verden. For political reasons, and to prevent the Swedes from advertising and recruiting mercenaries, the Allies decided to conquer these two duchies. Denmark and Brandenburg-Prussia were joined by allies from the neighbouring imperial principalities of Münster and the Duchy of Brunswick-Lüneburg. The campaign began on 15 September 1675 with an Allied advance into the two Swedish duchies. They rapidly captured one Swedish fortress after another. The Swedes were hampered by the high number of mainly German deserters because, after the imposition of the Imperial Ban it was forbidden to take up arms against member states of the Holy Roman Empire. By the end of the year only the Swedish headquarters town of Stade and Carlsburg were still in Swedish hands. In November the Allies sent their troops into winter quarters with the result that the conquest of the last remaining Swedish strongholds had to wait until the following year. Stade did not surrender until 13 August 1676. This theatre of war was nevertheless only of secondary importance for the Allies and for Sweden. At this point, the Swedish empire in Germany began to crumble. In 1675, most of Swedish Pomerania and the Duchy of Bremen were taken by the Brandenburgers, Austrians, and Danes.