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.
Fujiwara no Nagara
, also known as Fujiwara no Nagayoshi, was a Japanese statesman, courtier and politician of the early Heian period.
He was the grandfather of Emperor Yōzei.
Anna Kostka
Anna Kostka (1575–1635) was a Polish–Lithuanian noblewoman.
Anna was the daughter of Jan Kostka and Zofia Odrowąż, and related to Saint Stanislas Kostka.
She married Aleksander Ostrogski in 1592.
She inherited the city of Jarosław as well as several other areas after her mother.
After being widowed in 1603, she lived an independent life as the manager of her own and her children's dominions.
She benefited the university of Jarosław, introduced the Benedictine order to the city, protected the Jesuits, commissioned several later famed art objects for the churches and became known for her charity toward the poor.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Zofia Odrowąż
Zofia Odrowąż (1537–1580) was a Polish noblewoman.
She was the daughter of castellan and voivode Stanisław Odrowąż and only daughter of Anna of Masovia,
last Masovian duchess of the Piast dynasty, and became the widow of the castellan of Wojnicz and castellan of Sandomierz..
She married firstly, Hetman Jan Krzysztof Tarnowski and secondly, castellan and voivode Jan Kostka in 1569.
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.
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.
Guillaume Wittouck
Guillaume Wittouck( 1749- 1829) was a Belgian lawyer and High Magistrate.
He was the Grandfather of industrialist Paul Wittouck.

Question: Who is the maternal grandfather of Anna Kostka?