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.
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Henry Krause
Henry J." Red" Krause, Jr.( August 28, 1913 – February 20, 1987) was an American football offensive lineman in the National Football League for the Brooklyn Dodgers and the Washington Redskins.
He played college football at St. Louis University.
He is the grandfather of Jennifer Krause
He is the great grandfather of Payton Hoeing
Henry Wentworth
Sir Henry Wentworth of Nettlestead, Suffolk, KB( born c. 1448 – died between 17 August 1499 and 27 February 1501)," de jure" 4th Baron le Despencer, was the grandfather of Henry VIII's third wife, Jane Seymour, and the great- grandfather of Jane's son, Edward VI.
Henry Van Hoevenberg
Henry Van Hoevenberg Jr.( September 1, 1879 – September 18, 1955) was an American football player and coach.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Henry I van Vianden
Henry (or Hendrik)
van Vianden (died 4 June 1267) was a bishop of Utrecht from 1249 to 1267.
He was the son of Henry I, Count of Vianden and Margaret, Marchioness of Namur.
He was provost at Cologne before he was pushed forward as candidate for the bishopric of Utrecht by the Welfs in their struggle with the Hohenstaufen.
Pope Innocent IV then formally appointed him despite resistance from the canons of Utrecht.
Until 1252 he was bishop-elect, but in 1252 he was consecrated.
Henry supported the German anti-king William II of Holland, but William exploited the disputes that emerged between Henry, and the nobility and the city of Utrecht.
Henry managed to subdue his opponents, but their actions were a precursor to future struggles.
Henry van Vianden granted city rights to a large number of towns, such as Hasselt in 1252, Amersfoort in 1259, Goor in 1263, and Oudewater, Loenen and Vreeland in 1265.
In Vreeland he also constructed the Castle Vreeland as a border-fortress against Holland.
In 1254 he laid the first stone of the gothic Dom Church of Utrecht, after the previous church had burned down in a nine-day long city fire in 1253.
He was interred in the Dom church.
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.
Margaret, Marchioness of Namur
Margaret, Marchioness of Namur (c. 1194 – 17 July 1270) was ruling Marchioness of Namur in 1229-1237.
She was the daughter of Peter II of Courtenay and Yolanda of Flanders.
Fred Le Deux
Frederick" Fred" Le Deux( born 4 December 1934) was an Australian rules footballer who played with Geelong in the Victorian Football League( VFL).
He is the grandfather of Tom Hawkins.

Question: Who is Henry I Van Vianden's maternal grandfather?
Answer: Peter II of Courtenay