Question: Who is Landgravine Marie Louise Of Hesse-Kassel's maternal grandfather?

Knowledge 1: Landgravine Marie Louise of Hesse-Kassel
Marie Louise of Hesse-Kassel (7 February 1688 – 9 April 1765) was a Dutch regent, Princess of Orange by marriage to John William Friso, Prince of Orange, and regent of the Netherlands during the minority of her son and her grandson.She was a daughter of Charles I, Landgrave of Hesse-Kassel, and Maria Amalia of Courland.She and her husband are the most recent common ancestors of all currently reigning monarchs in Europe.Marie Louise is notable for having served as regent for two periods in Dutch history: during the reigns of her young son, William IV, Prince of Orange from 1711 and 1730, and of her young grandson, William V, Prince of Orange, from 1759 to 1765.She was often fondly referred to as Marijke Meu (Aunt Mary) by her Dutch subjects. [SEP] Knowledge 2: Maria Amalia of Courland
Maria Anna Amalia of Courland (12 June 1653 – 16 June 1711) was a Landgravine of Hesse-Kassel through her marriage on 21 May 1673 to her first cousin Charles I, Landgrave of Hesse-Kassel.She was the child of Jacob Kettler and Margravine Louise Charlotte of Brandenburg, eldest daughter of George William, Elector of Brandenburg.
Knowledge 1: Landgravine Marie Louise of Hesse-Kassel
Marie Louise of Hesse-Kassel (7 February 1688 – 9 April 1765) was a Dutch regent, Princess of Orange by marriage to John William Friso, Prince of Orange, and regent of the Netherlands during the minority of her son and her grandson.She was a daughter of Charles I, Landgrave of Hesse-Kassel, and Maria Amalia of Courland.She and her husband are the most recent common ancestors of all currently reigning monarchs in Europe.Marie Louise is notable for having served as regent for two periods in Dutch history: during the reigns of her young son, William IV, Prince of Orange from 1711 and 1730, and of her young grandson, William V, Prince of Orange, from 1759 to 1765.She was often fondly referred to as Marijke Meu (Aunt Mary) by her Dutch subjects. [SEP] Knowledge 2: Charles I, Landgrave of Hesse-Kassel
Charles of Hesse- Kassel( 3 August 1654 – 23 March 1730), of the House of Hesse, was the Landgrave of Hesse- Kassel from 1670 to 1730.
Knowledge 1: Landgravine Marie Louise of Hesse-Kassel
Marie Louise of Hesse-Kassel (7 February 1688 – 9 April 1765) was a Dutch regent, Princess of Orange by marriage to John William Friso, Prince of Orange, and regent of the Netherlands during the minority of her son and her grandson.She was a daughter of Charles I, Landgrave of Hesse-Kassel, and Maria Amalia of Courland.She and her husband are the most recent common ancestors of all currently reigning monarchs in Europe.Marie Louise is notable for having served as regent for two periods in Dutch history: during the reigns of her young son, William IV, Prince of Orange from 1711 and 1730, and of her young grandson, William V, Prince of Orange, from 1759 to 1765.She was often fondly referred to as Marijke Meu (Aunt Mary) by her Dutch subjects. [SEP] Knowledge 2: George Charles of Hesse-Kassel
George Charles of Hesse-Kassel (8 January 1691 – 5 March 1755) was a prince of Hesse-Kassel and a Prussian General.

Answer: Jacob Kettler