The Landgraviate of Hesse-Kassel (German: Landgrafschaft Hessen-Kassel), spelled Hesse-Cassel during its entire existence,, also known as the Hessian Palatinate (German: Hessischen Pfalz), was a state of the Holy Roman Empire. The state was created in 1567 when the Landgraviate of Hesse was divided upon the death of Philip I, Landgrave of Hesse.
Otto was the eldest son of Landgrave Maurice of Hesse-Kassel (1572-1632)  from his marriage to Agnes (1578-1602), the daughter of Count John George of Solms-Laubach (1546–1600) and his wife, Margaret of Schönburg-Glauchau (1554–1606).
Tuvo como capital durante breve tiempo a Marburgo y Gudensberg, pero desde 1277 su capital sería la ciudad de Kassel. Antes de 1500, el landgraviato había extendido sus límites hasta los ríos Rin y Neckar. Fue gobernado durante toda su historia por la Casa de Hesse .
El Landgrave Otto de Hessen-Kassel (24 de diciembre de 1594 en Kassel - 7 de agosto de 1617 en Hersfeld ), fue príncipe hereditario de Hesse-Kassel y administrador de la abadía de Hersfeld .
This is a list of monarchs of Hesse ( German: Hessen) during the history of Hesse on west-central Germany. These monarchs belonged to a dynasty collectively known as the House of Hesse and the House of Brabant,  originally the Reginar. Hesse was ruled as a landgraviate, electorate and later as a grand duchy until 1918.
Hesse-Kassel, former landgraviate of Germany, formed in 1567 in the division of old Hesse. In 1567 Hesse was partitioned among four sons of Landgrave Philip the Magnanimous, Hesse-Kassel going to William IV the Wise. Hesse-Kassel was the largest, most important, and most northerly of the four Hesse.
M Maurice, Landgrave of Hesse-Kassel O Otto the Younger W William I, Elector of Hesse William IV, Landgrave of Hesse-Kassel William VI, Landgrave of Hesse-Kassel William VII, Landgrave of Hesse-Kassel William VIII, Landgrave of Hesse-Kassel William V, Landgrave of Hesse-Kassel