By Alex Richards
The Swedish success at the Second Battle of Breitenfeld, coupled with the failures by the Imperial armies to expel the French and the increasing slide towards neutrality of many of the German Princes, finally convinced the Emperor Ferdinand to ratify the preliminary arrangements for the Westphalian Peace Conference in July 1642. The negotiations themselves began the following year, but there were still further twists to come on the Northern front of the war. Once again, the Danish were about to become involved in the conflict.
The Torstensson War
With the success of the Swedish war effort in Saxony, and the Emperor finally agreeing to the form of negotiations, Oxenstierna finally felt confident to move his focus to what many in the country regarded as Sweden’s true enemy: Denmark. Since the peace of Lübeck in 1629, Sweden’s main rival for control of the Baltic had been at peace, slowly rebuilding and growing more prosperous, in particularly from the Sound Tolls on traffic in and out the Baltic which she was able to collect by virtue of controlling both sides of the Kattegat. Sweden’s own ambitions to dominate the Baltic were stymied both by these, and by the continued Danish presence in Gotland and Ösel- now the Estonian island of Saaremaa, while Sweden also maintained a desire to acquire extensive lands within Danish-ruled Norway and Scania. Most concerningly for the Swedish, Denmark’s efforts since the Peace of Prague to position itself as a negotiating partner in the German conflict had secured the kingdom effective control over Bremen-Verden and Hamburg, while Christian IV was both offering himself as mediator for the peace conference and trying to force the dissolution of Sweden’s German army and a guarantee that they would gain no part of Pomerania as part of it. Oxenstierna’s domestic opponents meanwhile were accusing him of becoming bogged down in Germany and ignoring Sweden’s Baltic interests, which a conflict with Denmark would help to quieten.
If Oxenstierna was eager for war with Denmark, Torstensson was much less so. Saxony having refused to come to terms, he believed that the war in the Empire remained in too delicate a position to risk opening a second front, and spent most of 1643 attempting to push deeper into Habsburg territories. In this he was opposed by Gallas who concentrated his forces to form a block at Königgrätz while attempting to retake Olmütz. Meanwhile 4,000 cavalrymen under the Pomeranian General Krockow were sent in an attempt to retake his homeland, but a combination of the fortifications in western Pomerania and Königsmarck’s troops on garrison duty in Saxony forced him to retreat, arriving back in Breslau with only 1,200 men. The diversion was sufficient to blunt Torstensson’s ability to manoeuvre however, and while he was able to relieve Olmütz, he could press no further.
Come October 1643, orders sent from Stockholm four months earlier finally arrived indicating that Torstensson was to relocate and prepare for war with Denmark- a decision which he reluctantly complied with, abandoning some outer positions and telling the army they were heading for Pomerania on November 13th. The Swedish Riksdag authorised war with Denmark of November 26th, and Torstensson crossed the frontier into Holstein on December 16th, initially appearing to only be seeking winter quarters. The surprise of the invasion was completed on January 28th the following year when the Swedish declaration of war was finally delivered to Denmark, by which point Swedish forces had already seized Kiel and most of Holstein and Jutland had surrendered- though unlike the elites who tended to flee for Hamburg or Copenhagen, the peasantry remained stalwart in their attempts at resistance in many areas. General Horn followed this up with an invasion of Scania, while a smaller force moved to occupy Jämtland.
Swedish Reverses
Christian IV soon demonstrated why Danish forces were not to be discounted however. While Sweden had built up her navy to 38,000 tonnes and 58 warships, supplemented by a Dutch mercenary fleet of 32 ships, the Danish navy of 20,000 tonnes and 35 major warships was more experienced. With Christian IV himself joining the fleet, they managed to first defeat the Dutch ships- which while more numerous were significantly smaller than the Danish warships- bringing the crews to the point where they mutinied and returned to Amsterdam, then successfully trapped the main Swedish navy under Admiral Fleming in Kiel bay after a naval clash on July 11th that saw the Danish monarch loose an eye to flying splinters.
While no formal alliance emerged between Denmark and the Emperor, Ferdinand III sent Gallas north to take advantage of the situation, blockading Torstensson into Jutland with 18,000 men while contrary winds trapped the Swedish navy in the bay making them easy prey for Danish guns landed on the shore. Fleming lost his leg to one cannonball, forcing Wrangel to take charge of the Swedish navy and it was only a change in the winds direction on the night of August 12th that allowed the Swedes to escape from the area and prevent further losses. Meanwhile the appearance of the Imperial army allowed Denmark to focus on Sweden proper, relieving Horn’s siege of Malmö, retaking Jämtland and allowing Christian IV to consider an invasion of Sweden itself. Meanwhile in Stockholm Oxenstierna was already fielding concerned questions from both the Dutch- who were annoyed by the losses to their ships- and the French- who felt the entire war was a distraction from the true conflict in Germany. For a time the entire war appeared to be caught in the balance, and a Swedish defeat- or even a draw- would have had disastrous consequences in allowing Christian IV to push forward his own narrative in northern Germany, certainly guaranteeing him a role as an arbiter and guarantor of the peace in the Empire, and potentially allowing the Swedes to be blocked out from the post-war settlement entirely. Indeed, Torstensson had only managed to persuade his army to invade Denmark in the first place on the basis that Jutland had been little touched since 1629 and so would have fresher territory for over-wintering, and there was a significant faction amongst the mostly German army who viewed the whole endeavour as contrary to Swedish promises of protecting German Liberty and may well have mutinied in the event of a lengthy and seemingly unsuccessful campaign.
The Danish Collapse
However, the Imperial successes, at least, were based on weak foundations. Gallas had been forced to make a hasty rearrangement of his headquarters from Bohemia to Northwest Germany. The Swedes retained control of the towns of Mecklenberg, preventing his men from getting much in the way of supplies, and while they had captured Kiel and Rendsburg the men were on half-rations and there were shortages of draft animals to bring in vitally needed supplies. The Imperial army was effectively operating on a knifedge of combat readiness and at constant risk of a fatal collapse.
The trigger to this came from Wrangel and the Swedish fleet. Having regrouped, made repairs and rejoined with the remnants of the Dutch auxiliary fleet, they managed to catch the Danish fleet by surprise off Fehmarn island on October 23rd. With the Danish Admiral Mundt concluding that the Naval campaign was over for the year, half his ships were already laid up for the winter and the remainder were severely undermanned. The result was a catastrophe for the Danes- Mundt was killed trying to prevent the boarding of his flagship, a thousand Danish sailors were captured, multiple ships set on fire and only 3 managed to escape from the devastation. With control of the seas now secure Torstensson went on the offensive, forcing Gallas back up the Elbe into areas with little in the way of supplies to sustain his troops, whereupon he took heavily to drink and his subordinates scrambled to recover as much of the army as possible, while pinning the blame on their now heavily disgraced general. 3,000 men finally arrived in Wittenberg after a harsh retreat- though many of the losses would have been due to desertion rather than death- and Gallas was dismissed from his position the following January. Completing the litany of disasters for Denmark, Königsmarck swept through the Archbishopric of Bremen, pinning down the remaining Danish troops on the continent in the marshes of western Holstein, and effectively occupying the two territories by March 1645.
The triple blow was too much for Christian IV. After considering pawning Iceland and Scania to raise funds for a new army, the loss of his fleet and all diplomatic gains since 1629 led him to accede to French offers to mediate a peace, culminating in the Peace of Brömersbro on 13th August 1645. Ösel, Gotland, Jämtland and Härjedalen were ceded to Sweden, the strategic province of Halland was ceded for 30 years to guarantee the Danes would stick to a new toll arrangement, and Denmark essentially conceded influence in northern Germany to Sweden, recognising the autonomy of Hamburg and abandoning efforts to intervene at Westphalia. While Christian IV’s son, Frederick III, was able to come to a new agreement on taxing the nobility that supplemented the Royal finances in lieu of the Sound Tolls and allowed for the imposition of an absolutist government from 1660, the war marked the start of a 30 year period of decline that effectively broke Denmark’s position as a significant international player.
It had been a close-run thing, reliant entirely on catching the Danish navy unawares, but Oxenstierna’s gamble had paid off and his domestic critics were quieted.
Alex Richards is the author of Tippecanoe and Wallace Too, published by SLP