William I, Elector of Hesse

William I
Elector of Hesse
Portrait by Wilhelm Böttner, c. 1795
Landgrave of Hesse-Kassel
Reign	31 October 1785 – 27 February 1821
Predecessor	Frederick II
Successor	William II
Born	(1743-06-03)3 June 1743 Kassel, Hesse-Kassel, Holy Roman Empire
Died	27 February 1821(1821-02-27) (aged 77) Kassel, Hesse, German Confederation
Spouse	Princess Wilhelmina Caroline of Denmark ​ ​ (m. 1764; died 1820)​
Issue among others...	Marie Friederike, Duchess of Anhalt-Bernburg Karoline Amelie, Duchess of Saxe-Gotha-Altenburg Friedrich William II, Elector of Hesse Julius Jacob von Haynau (illegitimate)
House	Hesse
Father	Frederick II, Landgrave of Hesse-Kassel
Mother	Princess Mary of Great Britain
Religion	Calvinist

William I, Elector of Hesse (German: Wilhelm I., Kurfürst von Hessen; 3 June 1743 – 27 February 1821) was the eldest surviving son of Frederick II, Landgrave of Hesse-Kassel (or Hesse-Cassel) and Princess Mary of Great Britain, the daughter of George II.