By Alex Richards
Of the three main states left out of the Peace of Prague, arguably the most surprising at first glance was the decision to exclude the Landgraviate of Hesse-Kassel. While both Sweden and France were external to the Empire, and thus would logically have been excluded from any agreement defining itself as an internal restoration of order to create unity against exterior threats, Hesse-Kassel was not just a member of the Holy Roman Empire, but one of the most important states after Austria, the Electors and Bavaria. The explanation for this lies in the fact that Hesse-Kassel’s conflict with the Emperor, while intersecting with the underlying religious causes of the Thirty Year’s War, was fundamentally a separate war that happened to occurring at the same time as the wider conflict. It is this quality that makes the Hessian War one of the most idiosyncratic parts of the Thirty Years War. The Origins of the War The roots of the Hessian War stretch back to the 16th Century, but at heart are down to the practice of the Realteilung or Realerbteilungsrecht- which is a form of partible inheritance law- i.e. one where land is divided between all inheritors rather than just the eldest as in a primogeniture system. In the Holy Roman Empire this was specifically established using the Salic Succession laws- which held that inheritance could only pass through the male line, and any female line was ineligible to inherit, a system which meant that even distant cousins could be the closest heir to a given territory. What this means in practice, is that for those states which didn’t establish primogeniture as a standing House Law (which for the most part were the Electorates as these had much greater legal autonomy on such matters), any held territory was divided between all the sons of the last holder of the title, including all rights and status associated with this title. This is responsible for three things: the frequent hyphenated names given to states within the Empire which denote the subdivisions of a larger entity, such as Baden-Baden and Baden-Durlach; the extreme fragmentation of the Reichstag and other overarching bodies- where because the single vote given to a given territory would also be shared between the inheritors we see matters such as 12 different family members debating which way to vote on a given matter, or certain states being described as having 1/32 votes in the Reichstag; and most notably the extreme geographic fragmentation of the Empire. The most famous example of this fragmentation is Thuringia, where the application of the division laws to the lands of the various noble families led to, at one point, no less than 10 different Duchies of the Ernestine Saxon branch existing concurrently (eventually a recombination of these would give rise to the House of Saxe-Coburg-Gotha), as well as 5 territorial lines of the Electoral, Albertine Saxons; three branches of the House of Schwarzburg, and no less than 9 of the small Principality of Reuß.
In the case of Hesse, since the foundation of the House in 1264, the Landgraviate had been divided twice- from 1308 to 1311, and from 1458-1500, before the reign of Phillip I, known as the Magnanimous. Phillip had been an early champion of the Reformation, a leader of the Schmalkaldic League and a frequent opponent of the Emperor Charles V. Most importantly for our purposes, on his death in 1567 he divided his realm between his four sons from his first marriage- William IV of Hesse-Kassel, Louis IV of Hesse-Marburg, Phillip II of Hesse-Rheinfels and George I of Hesse-Darmstadt (confusingly all counted their numbering on from the previous unified Landgraves). Phillip II died in 1583, leaving his lands to William IV, followed by William himself in 1592 (leaving his lands to his son Maurice), and then George I (leaving his lands to his son Louis V). This left Louis IV, who as well as ruling over the prestigious University of Marburg had expanded his lands through purchasing the Fuldischen Mark from two branches of the House of Nassau, as the last survivor, but he too was childless and on his death divided his lands between his two nephews when he died in 1604. The following year, however, Maurice converted to Calvinism, and while his right to impose this faith on his subjects under the terms of the Peace of Augsburg was debatable considering the lack of recognition for Reformed Christians in the institutions of the Empire, of greater concern was his decision to impose it on the Hesse-Marburg lands- including the faculty of the University of Marburg- he had inherited. In response, Ludwig V laid claim to the other half of the Marburg inheritance. There followed a 19 year court case in the Reichshofrat between Hesse-Kassel and Hesse-Darmstadt, that eventually ruled in the latter’s favour in 1623. Hesse-Kassel was required by the terms of the ruling to not only relinquish the Marburg lands, but also the district of Schmalkalden and the County of Katzenelnbogen as a deposit. Combined with the costly legal fees and several disastrous interventions in neighbouring territories since his accession, Maurice had near-comprehensively lost the confidence of the nobility. The Hessian War While Hesse-Darmstadt remained initially neutral in the Thirty Years War, Hesse-Kassel was an enthusiastic supporter of the Palatine cause, swiftly giving his support to the Danish intervention in the conflict. While initially this put him on the upper hand, in the 1623 County Tilly advanced into the Hesses and summarily defeated Duke Christian of Brunswick-Wolfenbüttel, allowing him to occupy the majority of Hesse-Kassel and leading to the nobility suing for peace without Maurice’s consent. Maurice declared the negotiations treasonous, but only succeeded in losing his few remaining supporters in the nobility, and in response the estates forced him to abdicate in 1627, with his son William V taking the throne. Near simultaneously Louis V died laying siege to Rheinfels Castle in Katzenelnbogen as part of his efforts to claim the court-sanctioned provinces, being succeeded by his son George II.
This effectively defined the battleground for the remainder of the war between the two Hesses. Hesse-Darmstadt, having the legal backing of the Reichshofrat on their side, became the Emperor’s most significant Protestant supporter. Hesse-Kassel on the other hand was reliant on militarily enforcing their position and allied with first Sweden, and then France to try and secure the necessary international support to impose this. Territorial aims soon became inflated on both sides- William V, as has been mentioned before, seeking to expand his lands with the ecclesiastical territories of Westphalia, while George II attempted to parlay his cousin’s treachery into convincing the Emperor to assign the whole of the ancestral Hesse lands to his control. Meanwhile the 6 minor branches of the House of Hesse which had been given non-territorial lands under the jurisdiction of Hesse-Kassel or Hesse-Darmstadt by their respective family members for the most part spent the war attempting to maintain their lands as best as they could. Hesse-Kassel’s fortunes waxed and waned with those of the Protestant side in the war. Having come to an agreement with Hesse-Darmstadt over the division of lands in 1627, the latter managed to forge a treaty of neutrality with Sweden in 1631, which for the time being prevented Hesse-Kassel from being able to regain any lost territory here. Hesse-Darmstadt retaliated by claiming the whole of Hesse-Kassel after the Battle of Nördlingen, and followed this up by blocking any attempt to include Hesse-Kassel in the Peace of Prague. William V was, however, successful in preventing Imperial troops from taking the city of Hanau in 1636, and in response to this was placed under the Imperial Ban, and had his lands entirely occupied by Imperial forces. By this point, the conflict had become so long-running that the estates of both Hesse’s held a joint Landtag and attempted to mediate with the Emperor to find a compromise solution, but were unsuccessful given Vienna’s desire to completely defeat Hesse-Kassel, thus securing the Imperial position in Westphalia. William V and his family fled to East Frisia, where he soon died and was succeeded by his son William VI, under the regency of the newly widowed Landgravine Amalie Elizabeth. It is to her efforts for the remainder of the war that we shall turn to in the next article.
Alex Richards is the author of Tippecanoe and Wallace Too, published by SLP