Robert I, Duke of Burgundy
Robert I (1011 – 21 March 1076), known as Robert the Old and , was Duke of Burgundy from 1032 to his death.
Robert was son of King Robert II of France and Constance of Arles.
His brother was Henry I of France.
Agnes of France, Duchess of Burgundy
Agnes of France( c. 1260 – 19 December 1327) was a Duchess of Burgundy by marriage to Robert II, Duke of Burgundy.
She served as regent of Burgundy during the minority of her son in 1306 – 1311.
Ermengarde of Anjou, Duchess of Burgundy
Ermengarde of Anjou( – 18 March 1076), was a Duchess consort of Burgundy.
She was the daughter of Count Fulk III of Anjou and Hildegarde of Sundgau.
She was sometimes known as" Ermengarde- Blanche."
She married first, Geoffrey II, Count of Gâtinais( in French" Geoffroy"), called" Ferréol" and sometimes known as" Aubri", seigneur de Château- Landon.
Together they had the following children:
She married secondly Robert I, Duke of Burgundy.
Together they had one daughter:
Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.
Hildegarde of Burgundy
Hildegarde of Burgundy (–1104) was a French noble, Duchess consort of Gascony and Aquitaine by marriage to William VIII, Duke of Aquitaine.
She was the only daughter of Robert I, Duke of Burgundy with his second wife, Ermengarde of Anjou.
She was, and by marriage, Duchess of Gascony and Aquitaine.
She married William VIII, Duke of Aquitaine; she was his third wife.
William and Hildegarde had these children together:
William’s birth was a cause of great celebration at the Aquitanian court, but the Church at first considered him illegitimate because of his parents’ consanguinity.
This obliged his father to make a pilgrimage to Rome soon after his birth to seek papal approval of his marriage to Hildegarde.
Hugh IV, Duke of Burgundy
Hugh IV of Burgundy( 9 March 1213 – 27 or 30 October 1272) was Duke of Burgundy between 1218 and 1272.
Hugh was the son of Odo III, Duke of Burgundy and Alice de Vergy.
Florine of Burgundy
Florine of Burgundy( 1083–1097) was a French crusader.
She was the daughter of Eudes I, Duke of Burgundy and Sybilla of Burgundy.
Her maternal grandfather was William I, Count of Burgundy.
Florine was married to Sweyn the Crusader, a son of Sweyn II of Denmark.
Joan III, Countess of Burgundy
Joan III of Burgundy( 1/2 May 1308 – 10/15 August 1347), also known as Joan of France was a reigning Countess of Burgundy and Artois in 1330 – 1349, She was also Duchess of Burgundy by marriage to Odo IV, Duke of Burgundy.
She was the eldest daughter of King Philip V of France and Countess Joan II of Burgundy.
Sibylla of Burgundy, Duchess of Burgundy
Sybilla of Burgundy( 1065 – 1103), was a French noble, Duchess consort of Burgundy by marriage to Eudes I, Duke of Burgundy.
She was a daughter of William I, Count of Burgundy and Stephanie.
She was married to Eudes I, Duke of Burgundy in 1080.
Children:
Isabella of Bourbon
Isabella of Bourbon, Countess of Charolais( 1434 – 25 September 1465) was the second wife of Charles the Bold, Count of Charolais and future Duke of Burgundy.
She was a daughter of Charles I, Duke of Bourbon and Agnes of Burgundy, and the mother of Mary of Burgundy, heiress of Burgundy.

Question: Who is the paternal grandfather of Hildegarde Of Burgundy?
Answer: Robert II of France