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.
Henry III, Count of Schauenburg-Holstein
Henry III, Count of Schauenburg-Holstein (d. February 1421 in Bordesholm) was Bishop of Osnabrück as Henry I from 1402 to 1410, and also Count of Holstein-Rendsburg from 1404 until his death.
He was the youngest son of Henry II and his second wife Ingeborg of Mecklenburg-Schwerin.
John I, Count of Holstein-Kiel
John I, Count of Holstein- Kiel( – 20 April 1263) was a member of the House of Schauenburg.
He was Count of Holstein- Kiel from 1261 until his death.
Ingeborg of Mecklenburg-Schwerin
Ingeborg of Mecklenburg (1343/45 – 25 July 1395) was a daughter of Albert II, Duke of Mecklenburg and his wife, Euphemia of Sweden.
Euphemia was a daughter of Ingeborg of Norway, who was the only legitimate child of King Haakon V of Norway.
Thus, Ingeborg of Mecklenburg was Haakon V's great-granddaughter.
In 1360, she married Louis VI "the Roman" of Bavaria; she was his second wife.
The marriage remained childless.
After Louis's death, she married Henry II, Count of Holstein-Rendsburg.
They had at least four children:
Adolf IV of Holstein
Adolf IV( before 1205 – 8 July 1261), was a Count of Schauenburg( 1225 –1238) and of Holstein( 1227 – 1238), of the House of Schaumburg.
Adolf was the eldest son of Adolf III of Schauenburg and Holstein by his second wife, Adelheid of Querfurt.
Henry, Count of Looz
Henry( d. 2 August 1218), Count of Looz and Count of Duras, son of Gérard II, Count of Looz, and Adelaide of Gelderland, daughter of Henry I, Count of Guelders, and Agnes of Arnstein, daughter of Louis III of Arnstein.
Henry was Canon of St. Lambert in Liège, Provost of the Franciscans in Maastricht, and Provost of St. Alexander in Aschaffenburg.
Henry was Count of Looz for a few days in 1218, but died of poisoning.
He married Mechtild, daughter of Frederick III, Count of Vlanden.
Henry and Mechtild had one daughter:
He was succeeded as Count of Looz by his brother Arnold, and was the last recorded Count of Duras.
Reginar IV, Count of Mons
Reginar IV, Count of Mons( c. 950–1013) was the son of Reginar III, Count of Hainaut.
Lambert I of Leuven was his brother.
Henry III, Count of Gorizia
Henry III, Count of Gorizia( 1263- 1323) was a member of the Meinhardiner dynasty.
Henry Percy, 1st Earl of Northumberland
Henry Percy, 1st Earl of Northumberland, 4th Baron Percy, titular King of Mann, KG, Lord Marshal( 10 November 134120 February 1408) was the son of Henry de Percy, 3rd Baron Percy, and a descendant of Henry III of England.
His mother was Mary of Lancaster, daughter of Henry, 3rd Earl of Lancaster, son of Edmund, Earl of Leicester and Lancaster, who was the son of Henry III.
Adolf III of Holstein
Adolf III, Count of Schauenburg and Holstein( 1160 – 3 January 1225) was the ruler of the Counties of Schauenburg and Holstein.
He is particularly remembered for his establishment of a new settlement for traders on the banks of the Alster near the" Neue Burg" in Hamburg.

Question: Who is Henry Iii, Count Of Schauenburg-Holstein's maternal grandfather?
Answer: Albert II, Duke of Mecklenburg