Guillaume Wittouck
Guillaume Wittouck( 1749- 1829) was a Belgian lawyer and High Magistrate.
He was the Grandfather of industrialist Paul Wittouck.
Władysław of Oświęcim
Władysław of Oświęcim (1275/80 – by 15 May 1324), was a Duke of Oświęcim from 1315 until his death.
He was the eldest son of Mieszko I, Duke of Cieszyn by his wife, probably called Grzymisława.
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.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
Jan II of Oświęcim
Jan II of Oświęcim( – 19 February 1376) was a Duke of Oświęcim since 1372 until his death.
He was the only son of Jan I the Scholastic, Duke of Oświęcim, by his unknown first wife.
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.
Jan I the Scholastic
Jan I the Scholastic (1308/10 – 1372 before 29 September), was a Duke of Oświęcim from 1324 until his death.
He was the eldest child and only son of Duke Władysław of Oświęcim by his wife Euphrosyne, daughter of Duke Boleslaus II of Masovia.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Johan Braakensiek
Johan Coenraad Braakensiek( 24 May 1858, Amsterdam – 27 February 1940, Amsterdam) was a Dutch painter, illustrator and political cartoonist.
He is the grandfather of Jan van Oort.
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.

Question: Who is the paternal grandfather of Jan I The Scholastic?
Answer: Mieszko I, Duke of Cieszyn