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.
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.
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:
Hubba bint Hulail
Hubba bint Hulail was the grandmother of Hashim ibn' Abd Manaf, thus the great- great- great- grandmother of the Islamic" Nabī"( Prophet) Muhammad ibn Abdullah.
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.
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.
Tjuyu
Tjuyu( sometimes transliterated as Thuya or Thuyu) was an Egyptian noblewoman and the mother of queen Tiye, and the wife of Yuya.
She is the grandmother of Akhenaten, and great grandmother of Tutankhamun.
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.
Henry III, Count of Gorizia
Henry III, Count of Gorizia( 1263- 1323) was a member of the Meinhardiner dynasty.
Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.

Question: Who is Henry Iii, Count Of Schauenburg-Holstein's maternal grandmother?
Answer: Euphemia of Sweden