By Alex Richards
While the year 1646 had seen the first major peace negotiations of the Thirty Years War bear fruit, this by no means meant that it had been a year devoid of military action. In the absence of an Empire-wide truce, both sides still sought to utilise victories on the battlefield to strengthen their hands at the negotiating table, both for those agreements which had already been signed, though not ratified, and for those which were still under discussion.
The War in the Rhineland
With Denmark, Brandenburg and Saxony now decisively removed from the conflict, the only remaining significant forces in northern Germany in opposition to the Franco-Swedish alliance were Hesse-Darmstadt and the Archbishop-Elector of Cologne, both located along the Rhine to the southwest of where the Westphalian negotiators were gathered. While Hesse-Darmstadt was almost entirely engrossed in her long-running conflict with Hesse-Kassel over the disputed Marburg inheritance, Cologne had become increasingly relied upon as the final pillar of Imperial strategy in the north and west, and had effectively taken sole charge of running Imperial support for Spain’s military efforts in the Low Countries and the Moselle valley.
The Imperial army had itself been largely neutralised by the actions of 1645- the Saxon truce meant that the Oder was now the only viable route of attack from the Habsburg Crownlands against Sweden, and even there Imperial troops were too busy retaking the small towns of Lower Austria and Silesia to be able to push beyond them. This also made them useless for any attempt to support Bavaria, leading to the Archduke Leopold Wilhelm refusing to leave his billets in Franconia until May.
Königsmarck and Wrangel thus gathered in Thuringia with 15,000 cavalry and 8,000 infantry, along with another 17,000 Swedish conscripts scheduled to arrive from Sweden. Mindful both of the need to avoid compromising their negotiating position with a disastrous defeat and to give the French sufficient time to rebuild their own troops, Wrangel thus decided to target the easier target of Westphalia, in the process picking up 2,300 troops who Bönninghausen had tricked into being recruited to the Hessian army by pretending to be an Imperial recruiter. They attacked the cordon along the Weser in April, swiftly overrunning it and soon carried out a campaign of mass destruction and intimidation across the Archbishop-Electors territories east of the Rhine. Despite the destruction of lives, farms, churches and private property, Ferdinand of Cologne refused to back down relying on the enlarged Army of Westphalia for protection.
Archduke Leopold Wilhelm moved into the area, followed by Turenne in July, meaning there were now some 40,000 Imperial troops and 34,000 Franco-Swedish troops in the Rhineland, a concentration of troops which triggered Amalie-Elisabeth to launch her final attempt to resolve the Marburg inheritance in Hesse-Kassel’s favour. With Leopold Wilhelm initially distracted in his efforts to aid Hesse-Darmstadt, Wrangel and Turenne were able to slip past and march into Franconia and Württemberg unopposed at the end of August.
The Fall of Bavaria
The Archduke responded soon afterwards, leaving the two Hesses to resolve matters alone and marching through Bamberg to cross the Rhine at Regensburg. This left the Franco-Swedish force free to raid across the Lech, devastating western Bavaria as well as much of Swabia. Augsburg held out, as a bi-confessional council had recently been formed finally ending the internal divisions between the Catholics and Protestants of the city that had previously allowed armies to force entry, allowing the Archduke to relieve the three week siege of the city.
But while Leopold Wilhelm was able to prevent the fall of Augsburg on 12th October, the Imperial army was too exhausted to push further, effectively surrendering the rest of Swabia to the Franco-Swedish army. They consolidated their hold on the area around Lake Constance, overwintering at Isny-im-Allgau and conducting extensive raiding operations on what had been heretofore unaffected areas. Bregenz was sacked on January 4th 1647, leading to the seizure of 4 million florins of valuables which had been stored there by the surrounding communities. 2 weeks of plundering in the western Tyrol followed and by the spring Wrangel was blockading the Free City of Lindau while Turenne was besieging Überlingen.
Thus, in a manner that seems almost fitting for how long the war had dragged on for, the final fall of Bavaria came not from a grand military defeat but from simple exhaustion. With the continued defeats of the Imperial army over the past few years, and Leopold Wilhelm’s inability to prevent Wrangel or Turenne from consolidating their hold on Swabia, the Archduke resigned his commission, convinced he was no longer able to lead the army competently. His replacement was Gallas, and Elector Maximilian of Bavaria finally decided that the Imperial Army could no longer protect his lands from the enemy. While hoping for a general truce across the Empire, eventually the Elector bowed to French pressure and agreed to open negotiations for himself only at Ulm on 6th December 1646.
The negotiations lasted until March 14th the following year. Bavaria was granted much more lenient terms than Brandenburg or Saxony, but Heilbronn was surrendered to the French, and both Memmingen and Überlingen to the Swedes, in return for an evacuation of all troops from Western Bavaria. The Upper Palatinate was specifically excluded from the arrangement in order to allow the territory to be used as a route to invade Bohemia. More significantly, the Lower Palatinate and Augsburg were included were included in the deal, but only after the Elector agreed to also sign on behalf of his brother, Archbishop-Elector Ferdinand of Cologne.
With Ferdinand of Cologne now forced to eject the Imperial garrisons from his own territory, the Imperial position in the Rhineland effectively collapsed overnight. The agreement also created a domino effect of new truces. Trier had declared neutrality in 1645, now Archbishop-Elector Casimir of Mainz felt he had no choice to do the same, and signed his own truce on 9th May. The last of the Electors had now bowed of the war, most of the lesser princes had agreed to neutrality already and Spain’s position was teetering as Naples exploded into revolt. By the summer of 1647, the Emperor now stood alone against his enemies.
Alex Richards is the author of Tippecanoe and Wallace Too, published by SLP