Louise of Hesse-Kassel
Louise of Hesse-Kassel (7 September 1817 – 29 September 1898) was Queen of Denmark by marriage to King Christian IX of Denmark.
Princess Thyra of Denmark (1880–1945)
Princess Thyra of Denmark and Iceland (Thyra Louise Caroline
Amalie Augusta Elisabeth; Copenhagen, 14 March 1880 – Copenhagen, 2 November 1945) was the sixth child and third daughter of Frederick VIII of Denmark and his wife, Princess Louise of Sweden and Norway.
She was named for her paternal aunt, Princess Thyra of Denmark.
She died unmarried and without issue.
Princess Louise of Prussia (1808–1870)
Princess Louise of Prussia (1 February 1808 – 6 December 1870) was the third surviving daughter and ninth child of Frederick William III of Prussia and Louise of Mecklenburg-Strelitz.
Princess Louise of Denmark (1750–1831)
Princess Louise of Denmark and Norway( 20 January 1750 – 12 January 1831) was born to Frederick V of Denmark and Louise of Great Britain.
Her eldest daughter, Marie of Hesse- Kassel, was the wife of Frederick VI of Denmark.
Princess Caroline-Mathilde of Denmark
Princess Caroline- Mathilde of Denmark( 27 April 1912 – 12 December 1995) was a daughter of Prince Harald of Denmark and granddaughter of King Frederick VIII of Denmark.
As the wife of Knud, Hereditary Prince of Denmark, she became Hereditary Princess of Denmark.
Princess Louise of Denmark (1875–1906)
Princess Louise of Denmark ("Louise Caroline Josephine Sophie Thyra Olga")
(17 February 1875 – 4 April 1906) was a Danish princess, the third child and oldest daughter of Frederick VIII of Denmark and his wife, Princess Louise of Sweden and Norway.
Princess Louise of Thurn and Taxis
Princess Louise of Thurn and Taxis( 1 June 1859, Schloss Taxis, Dischingen, Kingdom of Württemberg – 20 June 1948, Sigmaringen, Germany)
Princess Dagmar of Denmark
Princess Dagmar of Denmark(" Dagmar Louise Elisabeth"; 23 May
1890 – 11 October 1961) was the youngest child and fourth daughter of Frederick VIII of Denmark and his wife, Princess Louise of Sweden and Norway.
Countess Maria Louise Albertine of Leiningen-Dagsburg-Falkenburg
Countess Maria Louise Albertine of Leiningen- Dagsburg- Falkenburg( 16 March 1729 – 11 March 1818); also known as Princess George, was heiress to the barony of Broich and by marriage Princess of Hesse- Darmstadt.
She was the grandmother and educator of Princess Louise of Mecklenburg- Strelitz, who later became Queen consort of Prussia.
Louise of Sweden
Louise of Sweden (Louise Josephine Eugenie ; 31 October 1851 – 20 March 1926), was Queen of Denmark as the spouse of King Frederick VIII.
She was the only surviving child of Charles XV of Sweden and his consort, Louise of the Netherlands.
She was the mother of both King Christian X of Denmark and King Haakon VII of Norway.

Question: Who is the maternal grandfather of Princess Louise Of Denmark (1875–1906)?
Answer: Charles XV of Sweden