By Alex Richards
When Amalie Elisabeth began her term as Regent of Hesse-Kassel for her son William VI, the Landgraviate was in a state of near-total defeat, her lands occupied by Imperial forces, and with Hesse-Darmstadt seeking to convert administrative rights in the territories to outright possession. When she relinquished the regency in 1650, however, the Landgraviate had successfully claimed much of the Hesse-Marburg inheritance and put Hesse-Kassel on the path to becoming the more powerful of the two major branches through the 18th and 19th Centuries. While the changing circumstances of the war at large did much to shape this, it was Amalie Elisabeth’s skill at adapting to these circumstances that truly allowed Hesse-Kassel to do more than simply survive the Thirty Years War.
Moves towards Peace
The initial situation was poor for Hesse-Kassel. Her lands (save for the garrisons of Kassel and Ziegenhain) had been occupied by the Imperial armies and were under the administration of Landgrave George II of Hesse-Darmstadt, who wished to claim them for himself. The Emperor desired the lands of the former Prince-Abbey of Hersfeld, and Amalie Elisabeth was in exile in the Netherlands, leaving her small, but well trained, army in East Frisia (albeit with their upkeep paid for at Dutch expense). Convinced that France would be unwilling to provide significant direct aid, she instead turned to the Dutch for assistance in reclaiming the rest of Kassel, but here too ran into difficulties as the Dutch did not wish to harm the good relations they had built up with the Elector of Cologne.
With Ferdinand II dying, and his more compromising son Ferdinand III becoming Holy Roman Emperor in 1637, the time looked to be ripe for a negotiated settlement. Ferdinand was willing to offer more concessions to secure peace and the restoration of his interests, while Amalie Elisabeth was, after all, a woman exercising power on behalf of a young son while in a weak position militarily and diplomatically. Ferdinand’s offer was, effectively, to produce a decisive result for the Hessian dispute while avoiding the more dramatic changes that could be engendered by its intersection with the wider war. Hesse-Kassel would surrender Marburg to Hesse-Darmstadt, and in return would retain the remainder of her territory and be allowed de facto freedom to practice Calvinism (as had already been agreed with Anhalt and Brandenburg). Ferdinand was even willing to renounce his own claims to Hersfeld and as a sign of good faith removed Landgrave George II of Hesse-Darmstadt as administrator over Hesse-Kassel and formally recognised Amalie Elisabeth as regent. Amalie Elisabeth, however, displayed the stubbornness characteristic of so many figures in the Thirty Years War and refused these terms, only eventually agreeing a truce on March 3rd 1638 which effectively placed the conflict on hold- The existing Hesse-Kassel garrisons (most of which were actually outside of Hesse-Kassel in the Westphalian bishoprics or East Frisia) were allowed to remain in place, but the majority of the Landgraviate remained occupied by Imperial forces, and the Hesse-Marburg inheritance and guarantee territories from the court proceedings remained with Hesse-Darmstadt.
The Resumption of Hostilities
The following year, Amalie Elisabeth concluded an alliance with France, the Guelph princes of Brunswick, and Sweden at Dorsten- a matter significant enough that Cardinal Richelieu himself was in attendance as the French representative. It is here that the Hessian War truly became enmeshed into the wider conflict of the Thirty Years War as, having previously conducted essentially parallel wars against Hesse-Darmstadt for the Hesse-Marburg inheritance, and against the Westphalian Ecclesiastical princes for territorial aggrandisement, Hesse-Kassel now essentially abandoned the former and focused entirely on militarily defeating the Electorate of Cologne, seeking to use this to create a stronger position to then regain the upper hand against Hesse-Darmstadt later.
While only part of a wider pivot in the conflict from south to north Germany that was occurring over the turn of the 1640s (and which will be covered in later articles), Hesse-Kassel’s existing positions in the Vest Recklinghausen and the Bishopric of Münster meant that she became a key element in the wider Franco-Swedish strategy, with her armies moving from small probing advances and raids towards Paderborn, to a full scale occupation of the nominally neutral duchy of Berg on the right side of Rhine, in tandem with the French occupation of Jülich on other side of the Electorate of Cologne- though avoiding the Spanish garrison in Jülich itself. Crucially Hesse-Kassel also occupied and heavily fortified Kalkar near the modern Dutch border, giving them a secure bridgehead across the Rhine and a communications link with France.
The Imperial response was reasonably swift, and while Ferdinand III had no ability as of yet to combat the French on the left bank of the Rhine, the dispersal of Hesse-Kassel’s troops in garrison duty, and the diversion of troops to assist in the Siege of Wolfenbüttel left Dorsten open to attack. Field Marshall Melchior, Count of Hatzfeldt, thus moved in with 20,000 troops and laid siege to the town on 16th July 1641. Unable to draw troops from the most strategically important siege at Wolfenbüttel, the fate of Dorsten was near certain from the beginning, especially after the walls were breached on 25th of August. When Hesse-Kassel’s commander in the town- Johann von Geyso- surrendered the town on 19th September of that year, he was allowed to leave with military honours, but this could not disguise the fact that the lynchpin of Hesse-Kassel’s control on the Right bank of the Rhine had been removed.
Paradoxically, therefore, it was in Jülich and the Electorate of Cologne proper that the army of Hesse-Kassel was most active for the time being, raiding extensively over Cologne’s lands, and culminating in the Battle of Kempen on 17th January 1642. Here, despite being out of supplies (which would have forced them to retreat to the Dutch Republic in the event of a defeat), the combination of 4,000 men (half infantry, half cavalry) under Hesse-Kassel’s Kaspar Graf von Eberstein and 5,500 mixed troops of France and Bernhard von Saxe-Weimar’s forces under the Comte de Guébriant caught Guillaume de Lamboy’s 9,000 Imperial troops unaware at breakfast- aided by the fact that a third of his troops were either incapacitated or underarmed- effectively destroying the Imperial army in the area before Hatzfeld could arrive on the scene.
Kempen, in the context of the wider war, was something of a footnote compared to the larger battles further east that year, but for Amalie Elisabeth it was arguably essential, providing her with a major victory, ensuring that the army of Hesse-Kassel would remain active and in the field, and reducing the number of Imperial troops in the immediate area that could oppose her.
The Return to Hesse-Darmstadt
By now the wider situation in the war was becoming dominated by the efforts to negotiate a final end to the conflict, and having put off attacking Hesse-Darmstadt again due to the diversion of troops to other conflicts, the movement of the conflict back to the area of the Main in 1645 gave Amalie Elisabeth the chance to attempt to regain the lands lost the decade before. As such, and working under the assumption that both France and the Emperor would be too distracted to intervene, an attempt was made to take Gießen in September 1645, followed by the shelling of Marburg a month later. Both of these efforts failed- the latter risking the ire of not just Hesse-Darmstadt but many of the other states with family members studying at the University there- but the following January von Geyso was given 6,000 battle-hardened troops freshly returned from assisting Swedish efforts elsewhere, and they successfully took Marburg on January 15th.
Hesse-Darmstadt responded by raising a new army, which very confusingly was commanded by Ernst Albrecht von Eberstein, a distant relative of the, now deceased, commander of Hesse-Kassel’s troops at Kempen, and aligned formally with the Emperor once more on 26th July 1646. Hesse-Darmstadt at this point appeared to regain the upper hand- retaking all the contested territories bar Marburg itself- but between a decisive defeat at the battle of Frankenburg and French attacks on Darmstadt, Hesse-Darmstadt was forced to agree to an unfavourable truce.
A Pyrrhic Peace?
Amalie Elisabeth attempted a sort of ‘salami slice’ technique over the next couple of years- taking advantage of the increasingly significant truces in the wider war to attack Hesse-Darmstadt once more in 1647 and successfully taking Rheinfels on 18th July, but the presence of Imperial troops allowed for Hesse-Darmstadt to retaliate and, though unable to regain Marburg, this spelt a decisive end to Amalie Elisabeth’s efforts to push Hesse-Darmstadt south of the Main.
By now, Amalie Elisabeth’s attempts to promote Calvinism in the Westphalian peace talks, together with the sheer scale of her territorial claims in the Ecclesiastical territories, which essentially consisted of the full territories originally promised by Gustavus Adolphus, had thoroughly annoyed even her closest allies, and with the war winding to a close, the Congress of Westphalia gave an ultimatum to both sides of April 2nd 1648 to accept arbitration. 12 days later, a settlement was agreed which saw Darmstadt retain Gießen and some smaller districts, but accept the loss of Marburg, Rheinfels, Katzenelenbogen and Schmalkalden. Administration of the University of Marburg was to be shared. Meanwhile France convinced Amalie Elisabeth to give up her territorial ambitions in return for 800,000 thalers, allowing her army to be paid off.
Hesse-Kassel had decisively established herself as the more powerful of the two Hesses, and over the next century would first secure the inheritance of Hanau, then gain wealth from exporting mercenaries (most famously to England during the American War of Independence), spend several decades in personal union with Sweden, and finally be briefly raised to an Electorate during Napoleon’s reorganisation of the Holy Roman Empire.
In the short term, however, it’s fair to say that the Hessian War had no true winner, given the sheer scale of the economic devastation suffered by the various lands of the two Landgraviates. Many of the staff and students of the University of Marburg had fled after the 1646 attack, and it’s re-founding in 1653 was effectively a merger and replacement of the equally battered University of Kassel. More widely, perhaps as much as half the population of the two Hesses was killed by war or epidemics over the course of the Thirty Years War, and even the most conservative estimates of 15% would still equate to a proportional death toll twice that of the Second World War. In microcosm, therefore, the Hessian War represents the scale of destruction that the wider war inflicted on Germany as a whole.
Alex Richards is the author of Tippecanoe and Wallace Too, published by SLP