Amalia Elisabeth, Landgravine of Hesse-Kassel
Amalia Elisabeth was regent of Hesse-Kassel for her son William VI from 1637-1650. Hesse-Kassel and Hesse-Darmstadt were the two territories remaining from Landgrave Philip I’s division of the territory among his four sons in 1567. The ruling line of the third remaining territory, Hesse-Marburg, had died out in 1604, leaving half to each of the remaining lines provided they upheld Lutheranism. However, the ruler of Hesse-Kassel had converted to Calvinism in 1603, causing Hesse-Darmstadt to dispute the inheritance. This was finally resolved by the Aulic Council in 1623 by granting Hesse-Darmstadt the entire remaining territory of Hesse-Marburg.
Defeated in the 1620’s, Hesse-Kassel became one of Sweden’s earliest and most fervent adherents. It profited from early Swedish victories, but was thrown on hard times again after the Battle of Nördlingen and the Peace of Prague (which it refused to accept because it did not permit Calvinism). Landgrave William V died in 1637, leaving Amalia Elisabeth at the head of a regency government for their eight-year-old son. She negotiated with both the Emperor and France, eventually agreeing to accept a French subsidy in exchange for continuing the war. The Hessian-Kassel army played a significant role for the remainder of the war, sending contingents to fight with both the French and Swedish armies, and maintaining and expanding control in Westphalia.
Amalia also had a significant role in the Congress of Westphalia. She urged France and Sweden to invite all Imperial estates to the negotiations to emphasize their role in diplomacy and to undermine the control that the Emperor and electors generally maintained. Along with Brandenburg, Hesse-Kassel contributed to the acceptance of Calvinism as one of the religions of the Empire.
In 1645, Amalia Elisabeth attacked Marburg in an attempt to overturn the Aulic Council’s ruling on the inheritance. She successfully held the town against an Imperial counterattack (although Imperial troops occupied Marburg at one point, they were unable to take the citadel and later had to withdraw) and forced Darmstadt into negotiations, which concluded with a new treaty on April 15, 1648. Amalia Elisabeth agreed to divide the Marburg inheritance, accepting compensation in Hersfeld and Schaumburg as compensation and an indemnity of 600,000 Imperial talers.
The Iron Princess: Amalia Elizabeth and the Thirty Years’ War (2013) by Tryntje Helfferich.