Princess Marie of Hesse-Kassel, second daughter of Prince Frederick of Hesse-Kassel, and his wife, Princess Caroline of Nassau-Usingen, was born at Hanau, Hesse-Kassel. Through her father, she was a great-granddaughter of George II of Great Britain. Her father's older brother was the Landgrave of Hesse-Kassel.
Landgrave of Hesse-Kassel. Frederick became Landgrave of Hesse only in 1730, ten years after becoming King of Sweden. He immediately appointed his younger brother William governor of Hesse. As Landgrave, Frederick is generally not seen as a success.
El 23 de agosto de 1866, con la Paz de Praga quedó disuelta la Confederación Germánica.Prusia se anexó Hannover y Hesse-Kassel; Austria cedió Holstein a Prusia, pagó indemnización de guerra y entregó el Véneto al Reino de Italia al firmar la Paz de Praga.