Guillaume Wittouck
Guillaume Wittouck( 1749- 1829) was a Belgian lawyer and High Magistrate.
He was the Grandfather of industrialist Paul Wittouck.
Countess Marie von Hochberg
Princess Marie of Hanover( born 26 November 1952 in Pattensen, Lower Saxony, Germany), is the wife of Count Michael von Hochberg.
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.
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.
Sophie of Merenberg
Countess Sophie Nikolaievna of Merenberg, Countess de Torby (1 June 1868 – 14 September 1927), also known as "Countess Torbay", was the elder daughter of Prince Nikolaus Wilhelm of Nassau and his morganatic wife, Natalia Alexandrovna Pushkina (who had been granted the title of Countess of Merenberg).
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.
Michael de la Bédoyère
Count Michael Anthony Maurice de la Bédoyère( 1900 – 1973) was an English author, editor and journalist.
Count Michael Mikhailovich of Torby
Count Michael Mikhailovich de Torby (8 October 1898 in Wiesbaden – 25 April 1959 in London) was the son of Grand Duke Michael Mikhailovich of Russia (1861–1929) and his morganatic wife Countess Sophie of Merenberg (1868–1927).
The great-grandson of Emperor Nicholas I of Russia and Alexander Pushkin.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.

Question: Who is the maternal grandfather of Count Michael Mikhailovich Of Torby?
Answer: Prince Nikolaus Wilhelm of Nassau