William II, Landgrave of Hesse-Wanfried-Rheinfels
William II, Landgrave of Hesse- Wanfried- Rheinfels( also known as" William the Younger"; born: 25 August 1671 in Langenschwalbach; died: 1 April 1731 in Paris, and also buried there) was a son of the Landgrave Charles of Hesse- Wanfried( 1649 – 1711) and his first wife, Sophie Magdalene of Salm- Reifferscheid( d. 1675).
He succeeded his father as Landgrave of Hesse- Wanfried and Hesse- Rheinfels.
After 1711, he styled himself" Landgrave of Hesse- Rheinfels".
Moritz, Landgrave of Hesse
Moritz, Prince and Landgrave of Hesse(" Moritz Friedrich Karl Emanuel Humbert" 6 August 1926 – 23 May 2013) was the son of Prince Philip, Landgrave of Hesse, and the head of the House of Brabant and the German House of Hesse.
Philip, Landgrave of Hesse-Philippsthal
Philip of Hesse- Philippsthal( 14 December 1655 – 18 June 1721) was the son of William VI, Landgrave of Hesse- Kassel and Hedwig Sophia of Brandenburg.
He was the first landgrave of Hesse- Philippsthal from 1663 to 1721 and the founder of the fifth branch of the house of Hesse.
Christine of Saxony
Christine of Saxony (25 December 1505 – 15 April 1549) was a German noble, landgravine of Hesse.
She was the regent of Hesse in 1547-1549.
She was the daughter of George the Bearded, Duke of Saxony and Barbara Jagiellon.
On 11 December 1523 in Kassel, she married Landgrave Philip I, Landgrave of Hesse.
The marriage was arranged to forge an alliance between Hesse and Saxony and was unhappy; Philip claimed to be disgusted by her and only shared her bed by duty.
They had ten children.
Whilst married to Christine, Philip practised bigamy and had another nine children with his other (morganatic) wife, Margarethe von der Saale; in 1540, Christine gave her consent to her husband's bigamy with his lover because of her view upon him as her sovereign.
Margarethe von der Saale, however, was never seen at court.
During Philip's absence and captivity in 1547-49, Christine was regent jointly with her oldest son.
Ernest, Landgrave of Hesse-Rheinfels
Landgrave Ernest of Hesse-Rheinfels-Rotenburg (8 December 1623 – 2 May 1693) was from 1649 to 1658 his death Landgrave of Hesse-Rheinfels and from 1658 until his death Landgrave of Hesse-Rheinfels-Rotenburg.
Because his brothers died young, all later Landgraves in the Rotenburg Quarter are descendants of Ernest.
Hence, Ernest is known as the ancestor of the Catholic Rotenburg Quarter, a group of junior lines of the House of Hesse.
William I, Elector of Hesse
William I, Elector of Hesse( 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.
Charles I, Landgrave of Hesse-Philippsthal
Charles I, Landgrave of Hesse- Philippsthal( 23 September 1682 – 8 May 1770) was a member of the House of Hesse and Landgrave of Hesse- Philippsthal from 1721 until his death.
Margravine Philippine of Brandenburg-Schwedt
Margravine Philippine Auguste Amalie of Brandenburg- Schwedt( 10 October 1745 – 1 May 1800) was a Landgravine consort of Hesse- Kassel by marriage to Frederick II, Landgrave of Hesse- Cassel.
Adelaide of Hesse
Adelaide of Hesse( after 1323 – after May 26, 1371) was a daughter of Henry II, Landgrave of Hesse, and his wife Elisabeth of Thuringia, daughter of Frederick I, margrave of Meissen.
Adelaide was a member of the House of Hesse.
Philip II, Landgrave of Hesse-Rheinfels
Philip II of Hesse-Rheinfels (1541, Marburg – 1583), also called "Philip the Younger", was the first Landgrave of Hesse-Rheinfels.
Philip was the third son of Landgrave Philip the Magnanimous and Christine of Saxony (1505–1549).
After his father's death in 1567, the Landgraviate of Hesse was divided between the four sons out of the late landgrave's first marriage.
Philip the Younger received the portion around the Rheinfels Castle and city of St. Goar on the left bank of the Rhine.
The county consisted mainly of the former Lower County of Katzenelnbogen with its four Ämter Rheinfels (with the city of St. Goar and the residence Rheinfels Castle) on the left bank of the Rhine, and Braubach, Reichenberg and Hohenstein on the right bank.
In 1569 Philip married Anna Elisabeth of Palatinate-Simmern, thereby becoming the son-in-law of the Elector Frederick III, one of the leaders of Calvinism.
Philip died on 30 November 1583 on castle Rheinfels.
As his marriage had remained childless, his territory fell to his elder brother Wilhelm IV, Landgrave of Hesse-Kassel (or Hesse-Cassel).
Philip was buried in St. Goar, where Wilhelm erected an imposing Renaissance monument.

Question: Who is Philip Ii, Landgrave Of Hesse-Rheinfels's maternal grandmother?
Answer: Barbara Jagiellon