Landgraviate of Hesse-Darmstadt
The Landgraviate of Hesse-Kassel originated in 1567 with the division of the Landgraviate of Hesse between the heirs of Philip I of Hesse ("the Magnanimous") after his death. Philip's eldest son, William IV, received Hesse-Kassel, which comprised about half the area of the Landgraviate of Hesse, including the capital, Kassel. William's brothers received Hesse-Marburg and Hesse-Rheinfels, but their lines died out within a generation and the territories then reverted to Hesse-Kassel and to the Landgraviate of Hesse-Darmstadt.