John IV, Duke of Brabant
John IV, Duke of Brabant( 11 June 1403 – 17 April 1427) was the son of Antoine of Burgundy, Duke of Brabant, Lothier and Limburg and his first wife Jeanne of Saint- Pol.
He was the second Brabantian ruler from the House of Valois.
Henry IV, Duke of Brabant
Henry IV of Brabant (1251/1252 – after 29 April 1272) was Duke of Brabant from 1261 to 1267.
Born at Leuven, he was the eldest son of Henry III, Duke of Brabant, and Adelaide of Burgundy.
Succeeding his father at about the age of ten, he proved infirm of mind and body, and was deposed in favor of his younger brother John I, Duke of Brabant.
After being deposed, Henry became a novice in Saint Bénigne Abbey in Dijon.
It is unknown what happened to Henry after 1272.
John III, Duke of Brabant
John III( 1300 – 5 December 1355) was Duke of Brabant, Lothier, and Limburg( 1312 – 1355).
He was the son of John II, Duke of Brabant, and Margaret of England.
Maria of Brabant, Duchess of Bavaria
Maria of Brabant( 1226–1256) was a daughter of Henry II, Duke of Brabant, and Maria of Swabia.
She married Louis II, Duke of Bavaria, being the first of three wives.
Marie of Évreux
Marie d' Évreux
( 1303 – October 31, 1335) was the eldest child of Louis d' Évreux and his wife Margaret of Artois.
She was a member of the House of Capet.
She was Duchess of Brabant by her marriage to John III, Duke of Brabant.
Her paternal grandmother being Marie of Brabant, she was a great- granddaughter of Henry III, Duke of Brabant and so, her husband's second cousin.
Marie was the eldest of five children born to her parents.
Marie's younger siblings included: Charles d' Évreux; Lord of Étampes, Philip III of Navarre; husband of Joan II of Navarre, and Jeanne d' Évreux; Queen of France by her marriage to Charles IV of France.
Henry Bryant (naturalist)
Henry Bryant( May 12, 1820 – February 2, 1867) was an American physician and naturalist.
He was the grandfather of Henry Bryant Bigelow.
Matilda of Brabant, Countess of Artois
Matilda of Brabant( 14 June 1224 – 29 September 1288) was the eldest daughter of Henry II, Duke of Brabant and his first wife Marie of Hohenstaufen.
Adelaide of Burgundy, Duchess of Brabant
Adelaide of Burgundy (c. 1233 – 23 October 1273) was a daughter of Hugh IV, Duke of Burgundy by his first wife Yolande of Dreux.
Alternatively, she was known as "Alice" or "Aledidis".
She was Duchess of Brabant as a result of her marriage to Henry III, Duke of Brabant in 1251 and would later act as regent of the Duchy following the death of her husband a decade later.
Henry III, Duke of Brabant
Henry III of Brabant (1230 – February 28, 1261, Leuven) was Duke of Brabant between 1248 and his death.
He was the son of Henry II of Brabant and Marie of Hohenstaufen.
The disputed territory of Lothier, the former Duchy of Lower Lorraine, was assigned to him by the German King Alfonso X of Castile.
Alfonso also appointed him Imperial Vicar to advance his claims on the Holy Roman Empire.
In 1251, he married Adelaide of Burgundy (1233 – October 23, 1273), daughter of Hugh IV, Duke of Burgundy and Yolande de Dreux, by whom he had four children:
Henry IV, Duke of Mecklenburg
Henry IV, Duke of Mecklenburg( 1417 – 9 March 1477) was from 1422 to 1477 Duke of Mecklenburg.

Question: Who is Henry Iv, Duke Of Brabant's maternal grandfather?
Answer: Hugh IV, Duke of Burgundy