Prince Sigismund of Prussia (1896–1978)
Prince William Victor Charles Augustus Henry Sigismund of Prussia (27 November 1896 at Kiel – 14 November 1978 at Esparza, Costa Rica), was the second son of Prince Henry of Prussia and his wife, Princess Irene of Hesse and by Rhine.
He was a nephew of Kaiser Wilhelm II and Tsarina Alexandra of Russia.
A great-grandson of Queen Victoria through both his parents
, he was the only one of three brothers who did not have the hemophilia common among her descendants.
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.
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.
Princess Charlotte of Prussia (1831–1855)
Princess Charlotte of Prussia( 21 June 1831 – 30 March 1855), was by birth a Princess of Prussia and member of the House of Hohenzollern and by marriage Hereditary Princess of Saxe- Meiningen.
She was the eldest child and daughter of Prince Albert of Prussia( younger son of Frederick William III of Prussia and Louise of Mecklenburg- Strelitz) and his first wife Princess Marianne of the Netherlands( daughter of William I of the Netherlands and Wilhelmine of Prussia).
Guillaume Wittouck
Guillaume Wittouck( 1749- 1829) was a Belgian lawyer and High Magistrate.
He was the Grandfather of industrialist Paul Wittouck.
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Princess Barbara of Prussia
Princess Barbara of Prussia (2 August 192031 May 1994) was the only daughter and elder child of Prince Sigismund of Prussia and Princess Charlotte of Saxe-Altenburg.
She was a great-granddaughter of Frederick III, German Emperor and a great-great-granddaughter of Queen Victoria.
On 17 September 1952 she was legally adopted by her paternal grandmother, Princess Irene of Prussia ("née" Princess Irene of Hesse and by Rhine), a granddaughter of Queen Victoria.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
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.

Question: Who is the paternal grandfather of Princess Barbara Of Prussia?
Answer: Prince Henry of Prussia