Nassau-Usingen. He was titular Landgrave of Hesse-Kassel-(Rumpenheim) and for many years heir presumptive to the throne of Hesse-Kassel. Prince William was born in
bought Rumpenheim Castle, Offenbach, from his brother Carl, and it became the family's seat. He became known as Landgrave of Hesse-Kassel-Rumpenheim, and
branch of the House of Hesse descended from the Prince Frederick of Hesse-Cassel. This branch, known as Hesse-Kassel-Rumpenheim, continued to live in the
Augusta of Hesse-Kassel, third daughter of Prince Frederick of Hesse-Kassel, and his wife, Princess Caroline of Nassau-Usingen, was born at Rumpenheim Castle