The Landgraviate of Hesse-Darmstadt came into existence in 1567, when
George, youngest of the four sons of Landgrave Philip I "the Magnanimous", received the Hessian lands in the former upper
County of Katzenelnbogen. His eldest brother
William IV received the
Landgraviate of Hesse-Kassel, while the second son
Louis IV obtained
Hesse-Marburg, and the third
Philip II became Landgrave of
Hesse-Rheinfels.
Hessian War The Hesse-Rheinfels line became extinct on Philip's death in 1583. When, in 1604, the childless Landgrave Louis IV of Hesse-Marburg died at
Marburg Castle, a succession dispute to his lands, along with the sectarian differences between
Calvinist Hesse-Kassel and
Lutheran Hesse-Darmstadt, led to a bitter, decades-long rivalry. Because the
University of Marburg had become Calvinist under the rule of Landgrave
Maurice of Hesse-Kassel, his cousin
Louis V of Hesse-Darmstadt founded the Lutheran
University of Giessen in 1607. The inheritance conflict was continued in the broader context of the
Thirty Years' War, in which Hesse-Kassel sided with the Protestant estates and Hesse-Darmstadt sided with the
Habsburg emperor. The
Hesse-Homburg and
Hesse-Rotenburg estates seceded from the opponents in 1622 and 1627. Though Hesse-Darmstadt and Hesse-Kassel reached an agreement in 1627, the quarrels rekindled, resulting
inter alia in the
Siege of Dorsten and culminating in a series of open battles from 1645, when the Kassel Landgravine
Amalie Elisabeth besieged Marburg. The conflict was finally settled on the eve of the 1648
Peace of Westphalia, more than eighty years after the division of the estates. Large parts of the disputed
Upper Hesse territory, including Marburg, fell to the elder Kassel line, while Hesse-Darmstadt retained
Giessen and
Biedenkopf.
18th–19th centuries In 1736, the Landgraves of Hesse-Darmstadt inherited the estates of the extinct Counts of
Hanau-Lichtenberg, again contested by their Kassel cousins. Hesse-Darmstadt gained a great deal of territory by the secularizations and mediatizations authorized by the
Reichsdeputationshauptschluss of 1803. Most notable was the acquisition of the
Duchy of Westphalia, formerly owned by the
Prince-Archbishop of Cologne, as well as territories from the
Prince-Archbishop of Mainz and the
Prince-Bishop of Worms. In 1806, upon the dissolution of the
Holy Roman Empire and the dispossession of his cousin, Elector
William I of Hesse-Kassel, Landgrave
Louis X joined the Napoleonic
Confederation of the Rhine and took the title of
Grand Duke of Hesse. ==Gallery==