Hesse is partitioned at the death of German Landgrave Philip of Hesse, also called Philip the Magnanimous, among his four sons.
Hesse-Kassel goes to William IV, who had participated with his brother-in-law Maurice of Saxony in the princely rebellion of 1552 that had liberated his father from his five-year captivity by the Holy Roman emperor Charles V.
Kassel becomes the capital of Hesse-Kassel, which is the largest, most important, and most northerly of the four new Hesse landgraviates.