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.
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.
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.
Madog ap Maredudd
Madog ap Maredudd (died 1160) was the last Prince of the entire Kingdom of Powys, Wales and for a time held the Fitzalan Lordship of Oswestry.
Madog was the son of Maredudd ap Bleddyn and grandson of Bleddyn ap Cynfyn.
He followed his father on the throne of Powys in 1132.
He is recorded as taking part in the Battle of Lincoln in 1141 in support of the Earl of Chester, along with Owain Gwynedd's brother Cadwaladr ap Gruffydd and a large army of Welshmen.
In 1149 he is recorded giving the commote of Cyfeiliog to his nephews Owain Cyfeiliog and Meurig.
The same year Madog was able to rebuild Oswestry Castle, a fortress of William Fitzalan.
It would seem likely that he had gained both the fortresses of Oswestry and Whittington in 1146.
Owain Fychan
Owain Fychan ap Madog (alternatively "Owain Vychan ap Madoc") (c.1125-1187).
Styled Lord of Mechain Is Coed and one of the sons of Madog ap Maredudd.
His mother was Susanna, daughter of Gruffudd ap Cynan.
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.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
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 Owain Fychan's paternal grandfather?
Answer: Maredudd ap Bleddyn