Margaret of Jülich
Margaret of Jülich (– 10 October 1425) was a daughter of Duke Gerhard VI of Jülich and his wife, Margaret of Ravensberg (1315-1389).
In 1369, she married Adolf III of the Marck.
She had fourteen children with him, at least five of whom did not survive infancy.
John I, Duke of Cleves
John I, Duke of Cleves, Count of Mark( 16 February 1419 – 5 September 1481) was Duke of Cleves and Count of Mark.
Gerhard I, Count of Holstein-Itzehoe
Gerhard I, Count of Holstein- Itzehoe( 1232 – 21 December 1290) was the only count of Holstein- Itzehoe.
Hedwig of Holstein
Hedwig of Holstein or Helvig( 1260 – 1324) was a Swedish queen consort, spouse of King Magnus III of Sweden.
She was the child of Gerhard I, Count of Holstein- Itzehoe( died 1290) and Elisabeth of Mecklenburg( died 1280).
Gerhard, Count of Mark
Gerhard, Count zur Mark (1378–1461) was the de facto ruler of the County of Mark between 1430 and 1461.
Dietrich was the third son of Count Adolf III of the Marck and Margaret of Jülich.<br
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His father had acquired the County of Cleves in 1368 and given this title to his eldest son Adolf.
The second son Dietrich received the title of Count of Mark.
When Dietrich fell in battle in 1398, he was succeeded as Count of Mark by his elder brother Adolf.
The ambitious Gerhard claimed a part of his father's territories for himself.
In 1423, it came to an armed conflict between Adolf and Gerhard, who had allied himself with the Archbishop of Cologne.
Peace was signed between the two brothers in 1430, and confirmed in 1437.
As a result, Gerhard ruled the largest part of Mark, but was to be succeeded by his nephew John.
Gerhard died in 1461 without children and the County of Mark and Duchy of Cleves were reunited again in a personal union under John I.
Kaoru Hatoyama
After the elections of 2009, she became more widely known as the grandmother of Prime Minister Yukio Hatoyama and his politician brother Kunio Hatoyama.
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.
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.
Hannah Arnold
Hannah Arnold, also known as Hannah Waterman King, was the grandmother of Benedict Arnolds children.
Dietrich IX, Count of Mark
Dietrich IX, Count of Mark( 1374 – 1398) was the Count of Mark from 1393 until 1398.
Dietrich was the second son of Count Adolf III of the Marck and Margaret of Jülich.
His father had acquired the County of Cleves in 1368 and reserved this title for his eldest son Adolph to succeed him after his death.
Dietrich already received the title of Count of Mark in 1393, when his father was still alive.
When Dietrich fell in battle in 1398, he was succeeded by his elder brother Adolph, who had become Count of Cleves in 1394.
Thus the County of Mark and the County of Cleves were reunited again.

Question: Who is the maternal grandmother of Gerhard, Count Of Mark?
Answer: Margaret of Ravensberg