Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Eric IV of Denmark
Eric IV, also known as Eric Ploughpenny or Eric Plowpenny,( – 10 August 1250) was king of Denmark from 1241 until his death in 1250.
He was the son of Valdemar II of Denmark by his wife, Berengaria of Portugal, and brother of King Abel of Denmark and King Christopher I of Denmark
Princess Caroline-Mathilde of Denmark
Princess Caroline- Mathilde of Denmark( 27 April 1912 – 12 December 1995) was a daughter of Prince Harald of Denmark and granddaughter of King Frederick VIII of Denmark.
As the wife of Knud, Hereditary Prince of Denmark, she became Hereditary Princess of Denmark.
Dorothea of Brandenburg
Dorothea of Brandenburg( 1430/ 1431 – 10 November 1495) was Queen consort of Denmark( 1445 –1448 and 1449 – 1481), Norway( 1445–1448 and 1450 – 1481), and Sweden( 1447 – 1448 and 1457 – 1464) two times each by marriage to Christopher of Bavaria and Christian I of Denmark.
She served as interim regent during the interregnum in 1448, and as regent in the absence of her second spouse during his reign.
She was the mother of two future kings of Denmark:
John, King of Denmark who reigned from 1481 until 1513; Frederick I of Denmark who reigned from 1523 until 1533.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Prithvipati Shah
Prithvipati Shah( ?–1716) was the king of the Gorkha Kingdom in the Indian subcontinent, present- day Nepal.
He was the grandfather of Nara Bhupal Shah.
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.
Berengaria of Portugal
Berengaria of Portugal (c. 1198 – 27 March 1221) was a Portuguese "infanta" (princess) and Queen of Denmark, by marriage to King Valdemar II.
She was the fifth daughter of King Sancho I of Portugal and Dulce of Aragon.
She was the mother of Danish kings Eric IV, Abel and Christopher I.
Christopher I of Denmark
Christopher I  (1219 – 29 May 1259) was King of Denmark between 1252 and 1259.
He was the son of Valdemar II of Denmark by his second wife, Berengaria of Portugal.
He succeeded his brothers Eric IV Plovpenning and Abel of Denmark on the throne.
Christopher was elected King upon the death of his older brother Abel in the summer of 1252.
He was crowned at Lund Cathedral on Christmas Day 1252.

Question: Who is Christopher I Of Denmark's maternal grandfather?
Answer: Sancho I of Portugal