Question: Who is the maternal grandfather of Princess Louise Of Belgium?
Answer: Archduke Joseph, Palatine of Hungary

Marie Henriette of Austria (Marie Henriette Anne; 23 August 1836 – 19 September 1902) was Queen of the Belgians as the wife of King Leopold II. Marie Henriette was one of five children from the marriage of Archduke Joseph, Palatine of Hungary, and Duchess Maria Dorothea of Württemberg. Marie Henriette was a cousin of Emperor Ferdinand I of Austria, and granddaughter of Leopold II, Holy Roman Emperor, through her father