The Bremen-Verden campaign (German: Bremen-Verdener feldzug) was a conflict during the Northern Wars in Europe. From 15 September 1675 to 13 August 1676 an anti-Swedish coalition comprising Brandenburg-Prussia, the neighbouring imperial princedoms of Lüneburg and Münster, and Denmark-Norway, conquered the Duchies of Bremen and Verden.
Bremen-Verden, a remote outpost of Sweden's Baltic Sea empire, was the third Swedish imperial fief in North Germany granted under the Peace of Westphalia in 1648, alongside Swedish Pomerania and the Barony of Wismar. Following its conquest it remained in allied hands until the end of the war in 1679, but was then fully returned to Sweden in the wake of the Treaties of Nijmegen. For the major warring parties of Sweden, Brandenburg and Denmark, this theatre of war in northwest Germany was only of secondary significance.
Background
After France had invaded the General States in 1672 as retribution for the outcome of the War of Devolution, an alliance formed up against her. The conflict escalated into the Dutch War. In order to relieve her increasingly stretched forces, therefore, France urged its traditional ally, Sweden, to go to war against her enemies, who, in addition to the States General, included the House of Habsburg and the Electorate of Brandenburg. At the end of 1674, a Swedish army under the imperial commander, Carl Gustav Wrangel, invaded the Margraviate of Brandenburg which was militarily almost unprotected, while the Brandenburg army under Elector Frederick William I found itself at war with France. In a short summer campaign in 1675, Frederick William succeeded in defeating the Swedish army and pushing it back to Swedish Pomerania.
Encouraged by the Brandenburg victory, on 17 July 1675 the imperial ban was imposed on the Swedish king in his capacity as an imperial prince in Pomerania, Mecklenburg and Bremen-Verden. A Reichsexekution was declared by the Holy Roman Empire against Sweden. The Westphalian and Upper Saxon Circles were charged with the enforcement of the ban against the Swedes. A little later came the declaration of war by Denmark on Sweden.
In this large-scale war, the Allies, Denmark-Norway and Brandenburg, initially intended to conquer the Swedish possessions in northern Germany, then turn use their full might in the theatres of war in Scania. But with the conquest of Bremen-Verden, located on the southern border of Denmark, Sweden would have secured a potential springboard against Denmark. Another political power factor was that it would give the Swedes opportunities to recruit mercenaries.
The war planning that took place on the Swedish homeland envisaged military victory being achieved through the deployment of the Swedish fleet which was likely to defeat the Danish-Norwegian fleet in the Baltic Sea, thus relieving Sweden's North German possessions, so it could then, in a further step, land on Zealand, the heart of Denmark. Sweden's chances in the Duchy of Bremen-Verden, therefore, lay principally in the strength of her own fleet, which was to have ensured a military victory by dispatching additional troops from the motherland. However, since the Swedish fleet could not sail due to delays in equipment, Bremen-Verden was not reinforced and had to rely on its in-place forces.
Sweden's forces in the Duchy of Bremen-Verden were numerically weak and distributed across several fortified bases. The bulk of the Swedish army was in Stade, Carlsburg and seven other small fortresses. They would only be able to oppose large scale offensive operations with delaying tactics. The Swedish defence plans were based on siege warfare. The number of the fortified places would force her potential opponents, to fight a series of arduous, small sieges, but it also fragmented the troops available to the defenders and prevented them from forming a mobile field army.
Diplomatic preparations
The Roman Catholic Prince-Bishop of Münster, Christoph Bernhard von Galen, who was intent on extending his power and who, until 22 April 1674, sided with France in battle against the Netherlands, signed an agreement on 7 June 1675 with the imperial court in Vienna that obliged him to supply 9,000 troops "to the Emperor and for Imperial Service". As a result of this obligation, the bishop was made to participate in the war against Sweden. On 11/21 September 1675 a treaty of neutrality was signed between the Allies, the Prince-Bishopric of Münster, Denmark and Brandenburg on the one hand and John Frederick of Brunswick-Lüneburg on the other. Brunswick-Lüneburg, which hitherto had been on the Swedish side, therefore, agreed to remain neutral in the upcoming fight against Sweden.
That treaty between the four allies was signed primarily because it was in the political interests of the imperial princes involved, rather than in discharge of their obligation to defend the circle or empire. Thus the execution of the imperial ban was carried out by the respective territorial armies, while the circle troops took no significant part in the fighting.
Autumn 1675 campaign
Invasion of Bremen-Verden by the Münster army
The campaign began on 15 September 1675 in the southwest of the Swedish territory when, according to the reports of the Theatrum Europaeum, about 10,000 men – according to other records 4,000 men – of the Prince-Bishop of Münster passed through Haselünne and invaded the Swedish Amt of Wildeshausen. They continued their advance to the River Weser unimpeded. On 25 September at Bremen, Münster's artillery fired across the Weser.
A Brandenburg force of 1,600 infantry and 700 cavalry under Major General Freiherr von Spaen, coming from Westphalian territory, also arrived in Bremen at the end of September. The Danes participated with 2,500 men under the orders of Count Gustavus Adolphus of Baudissin.
The Münster troops under Prince-Bishop von Galen marched from neutral Bremen to the fortress of Langwedel on the Weser, capturing it on 27 and 28 September. With that, the way into the state of the former Prince-Bishopric of Verden was open. Verden upon Aller itself fell into Allied hands on 27 September. Münster forces suddenly invaded the town and established themselves at one of the town gates.
After Verden the town of Rotenburg was conquered, falling after some resistance. From there the marching column pressed on immediately towards Ottersberg, which was taken on 3 October 1675 by the now seasoned troops of the Prince-Bishop of Münster. The roughly 140 man Swedish garrison were taken prisoner. The Allied army then marched in a northeasterly direction with Buxtehude as their objective, reaching it on 12 October.
Buxtehude was well fortified, had plenty of food and munitions and, according to the Theatrum Europaeum, a garrison of nearly 400 men. A siege appeared inevitable. After occupying an important eminence in front of the town that same day, the Allies drew up all their artillery of 14 mortars and 37 cannon into battery positions. Shelling commenced on the morning of 13 October, setting fire to over 60 houses. On 14 October a total of 100 mortar bombs and 60 artillery shells were fired into the town from howitzers and mortars, again wreaking much damage, but without causing a single fatality. On 15 October, fire was lifted in order for the trenches necessary for an assault on the town to be prepared and in order to launch an all-out attack.
Because the shelling had already resulted in heavy damage, the Buxtehude commandant, Hamelton, was forced to surrender the town having been implored by its citizens and his German mercenaries who had learned of the pronouncement of the Imperial Ban on Sweden. The garrison was permitted to withdraw to Stade taking its belongings and side arms. On 16 October the Allies entered the town, 24 cannon and their munitions falling into their hands as a result.
After the fall of Buxtehude several Allied regiments pushed forward towards Bremervörde. On 25 October the siege of Bremervörde Fortress began. After three days of heavy shelling the mercenaries, who were mainly German, refused to render military service for the garrison. The Allies sent a trumpeter into the town as a parlimentaire. He threatened the garrison that all German combatants would be executed when the fortress was captured. The threat was based on the fact that they had used their weapons in the service of an outlaw against the Holy Roman Empire. In view of the situation, the Swedish commander had no choice but to surrender the place. The Swedish officers and men were given free passage with all their possessions and weapons, whilst most of the Germans transferred to the Allied side. As the result of a previous agreement amongst the Allies, the town had been promised to the Lüneburg troops who entered Buxtehude with 500 men. At this time on the fortresses of Carlsburg and Stade remained in Swedish hands.
Brandenburg and Danish landing operations
In parallel with the advance of Münster, Brandenburg and Danish troops, there were two unsuccessful landing attempts by Danish and Brandenburg forces, that were repulsed by the Swedes with heavy losses. The first landing operation, at the end of September, was carried out near Carlshagen by a Brandenburg formation under Admiral Simon de Bolfey, in order to conquer the strategically important Carlsburg Fortress on the Weser. This Swedish fortress had been first constructed in 1672 with the task of controlling the mouth of the Weser. Approaching from the River Elbe, a Brandenburg squadron of seven ships appeared, with a landing force of 534 men; together with the ships' complements, the whole force comprised about 800–900 men.
On 28 September, the troops were landed near Lehe, north of Carlsburg. Because the Swedish commander of Carlsburg, which was relatively strongly defended by about 800 soldiers, refused to surrender, the Brandenburg admiral, de Bolfey, had his troops erect earthworks in front of the town and, on 30 September, opened fire with several salvoes from his ships' guns. However, on the same day the landing force pulled back from its positions in front of the fortress, in the course of which 30 Brandenburg soldiers switched sides to join the Swedes. Encouraged by the statements of these deserters, on 1 October the Swedes launched an attack with 200 men, but had to withdraw with losses after a brief fight.
In order to relieve Carlsburg Fortress, 13 squadrons of cavalry were dispatched there from Stade under the command of Lieutenant Colonel Sidon. The Brandenburgers, who were now clearly outnumbered, were informed by scouts of the approaching force. They lifted the siege and embarked on the ships again on 2 October. Due to unfavourable winds, the ships, now loaded with the infantry, found themselves close to the shore as the Swedish reinforcements arrived. Consequently, they were attacked by the Swedes and, after resisting a short time, had to capitulate to superior forces. Total losses suffered by the Brandenburg force during this operation came to 314 men, the majority taken prisoner.
Roughly at the same time, a Danish flotilla landed six companies of infantry under Lieutenant Colonel Harwich on the territory of Land Wursten. But after their successful defence of Carlsburg, the Swedish units under Sidon attacked these Danish mercenaries. After several battles on 4 October, the Swedes succeeded in defeating the Danes and taking 400 of them prisoner. Of these, 200 were then taken into Swedish service and ordered to reinforce the garrison at Carlsburg. The other prisoners were held (untergesteckt) in Stade. The main body of the Swedish troops returned to Stade on 7 October. The naval blockade of Carlsburg was lifted and the seven Brandenburg ships repaired instead to the River Elbe in order to cut off the seaward supply route to the town of Stade.
By contrast, Carlsburg was besieged again in late October, despite the Swedes previous successful defence of the town.
Allied change of command
In October about 3,000 men of the Principality of Lüneburg under the command of Duke George William of Brunswick-Lüneburg arrived in the theatre of war from the Rhineland. As the appointed circle colonel of the Lower Saxon Circle, the duke took overall command of the now 12,000 strong Allied army.
In the headquarters of Prince-Bishop von Galen in Rotenburg a secret treaty was signed on 14 October, wherein the Prince-Bishop, Duke George William and Duke Rudolph Augustus of Brunswick-Wolfenbüttel agreed to provide mutual support to one another in the ensuing campaign. Furthermore, a provisional division of the conquests was negotiated that excluded Denmark and Brandenburg.