Guillaume Wittouck
Guillaume Wittouck( 1749- 1829) was a Belgian lawyer and High Magistrate.
He was the Grandfather of industrialist Paul Wittouck.
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.
Nicodemus Tessin the Younger
Count Nicodemus Tessin the Younger( May 23, 1654 – April 10, 1728) was a Swedish Baroque architect, city planner, and administrator.
The son of Nicodemus Tessin the Elder and the father of Carl Gustaf Tessin, Tessin the Younger was the middle- most generation of the brief Tessin dynasty, which have had a lasting influence on Swedish architecture and history.
Niclas Gustaf Duncan
Niclas Gustaf Duncan( 20 November 1711 – 23 April 1771) was a Swedish post official and spy.
Between 1743 and 1748, he was active as an agent of Carl Gustaf Tessin to act as a double agent in Swedish service and spy on the Russian diplomat Johann Albrecht Korff under the protect of acting as his spy on Herman Cedercreutz, who was the Swedish envoy in Russia at the time.
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Hedvig Eleonora Stenbock
Hedvig Eleonora Stenbock (1658–1714) was a Swedish noblewoman and lady-in-waiting; daughter of Count Erik Stenbock and related to queen Katarina Stenbock; sister of the political salonist Magdalena Stenbock.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
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.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Carl Gustaf Tessin
Carl Gustaf Tessin (5 September 1695 – 7 January 1770) was a Swedish Count and politician and son of architect Nicodemus Tessin the Younger and Hedvig Eleonora Stenbock.
He was one of the most brilliant personages of his day, and the most prominent representative of French culture in Sweden.
He was also a fine orator.
Tessin's art collection became the original core of the collection of Sweden's Nationalmuseum.

Question: Who is the maternal grandfather of Carl Gustaf Tessin?
Answer: Erik Stenbock