The Swedish invasion of Brandenburg (1674–75) () involved the occupation of the undefended Margraviate of Brandenburg by a Swedish army launched from Swedish Pomerania during the period 26 December 1674 to the end of June 1675. The Swedish invasion sparked the Swedish-Brandenburg War that, following further declarations of war by European powers allied with Brandenburg, expanded into a North European conflict that did not end until 1679.
The trigger for the Swedish invasion was the participation of a 20,000 strong Brandenburg Army in the Holy Roman Empire's war on France as part of the Franco-Dutch War. As a result, Sweden, a traditional ally of France, occupied the militarily unprotected margraviate with the declared aim of forcing the Elector of Brandenburg to sue for peace with France. In early June 1675 the Elector and his 15,000 strong army decamped at Schweinfurt in Franconia, now southern Germany, and reached the city of Magdeburg on . Elector Frederick William, led the campaign against a Swedish force of between 11,000 and 12,000 men. After one week the Swedish troops had retreated from the Margraviate of Brandenburg.
Background
After the War of Devolution, Louis XIV, King of France, pressed for retribution against the States-General. He initiated diplomatic activities with the aim of isolating Holland completely. To that end, on 24 April 1672 in Stockholm, France concluded a secret treaty with Sweden that bound the Scandinavian power to contribute 16,000 troops against any German state that gave military support to the Republic of Holland.
Immediately thereafter, in June 1672, Louis XIV invaded the States-General - thus sparking the Franco-Dutch War - and advanced to just short of Amsterdam. The Elector of Brandenburg, in accordance with treaty provisions, supported the Dutch in the fight against France with 20,000 men in August 1672. In December 1673, Brandenburg-Prussia and Sweden concluded a ten-year defensive alliance. However, both sides reserved freedom to choose their alliances in the event of war. Because of his defensive alliance with Sweden, during the period that followed the Elector of Brandenburg did not expect Sweden to enter the war on the French side. And despite the separate Treaty of Vossem agreed between Brandenburg and France on 16 June 1673, Brandenburg rejoined the war against France in the following year, when the emperor of the Holy Roman Empire declared an imperial war (Reichskrieg) against France in May 1674.
On 23 August 1674, therefore, a 20,000 strong Brandenburg army marched out again from the Margraviate of Brandenburg heading for Strasbourg. Elector Frederick William and Electoral Prince Charles Emil of Brandenburg accompanied this army. John George II of Anhalt-Dessau was appointed Statthalter ("Governor") of Brandenburg.
Through bribes and by promising subsidies France now succeeded in persuading its traditional allies, Sweden, which had only escaped losing all of Pomerania with France's intervention in the Treaty of Oliva in 1660, to enter the war against Brandenburg. The decisive factor was the concern of the Swedish royal court that a French defeat would result in the political isolation of Sweden. The goal of Sweden's entry into the war was to occupy the undefended state of Brandenburg in order to force Brandenburg-Prussia to withdraw its troops from war zones in the Upper Rhine and the Alsace.
Preparations for war
The Swedes then began to assemble an invasion force in Swedish Pomerania. From September more and more reports of these troops movements were received in Berlin. In particular, the Governor of Brandenburg notified his Elector in early September of a conversation with the Swedish envoy, Wangelin, in which he had announced that about 20,000 Swedish troops would be available in Pomerania before the end of the month. The news of an impending attack by the Swedish army grew stronger when, in the second half of October, the arrival in Wolgast of the Swedish commander-in-chief, Carl Gustav Wrangel, was reported.
John George II of Anhalt-Dessau, clearly troubled by news of the troop build-up, asked Field Marshal Carl Gustav Wrangel several times in late October, through Brandenburg colonel, Mikrander for the reasons for these troop movements. Wrangel, however, failed to answer and refused another attempt at dialogue by the Prince of Anhalt In mid-November the governor, John George II, had received assurance of an impending Swedish invasion, but in Berlin the exact causes and motives for such imminent aggression remained unclear.
