Raymond of Poitiers
Raymond of Poitiers (c. 1099- 29 June 1149) was Prince of Antioch from 1136 to 1149.
He was the younger son of William IX, Duke of Aquitaine and his wife Philippa, Countess of Toulouse, born in the very year that his father the Duke began his infamous liaison with Dangereuse de Chatelherault.
Paul the Jew
Paul the Jew was the Patriarch of Antioch, and head of the Greek Orthodox Church of Antioch, from 519 to 521.
Sibylla, Queen of Jerusalem
Sibylla (French: "Sibylle", c. 1160–1190) was the Countess of Jaffa and Ascalon from 1176 and Queen of Jerusalem from 1186 to 1190.
She was the eldest daughter of Amalric I of Jerusalem and Agnes of Courtenay, sister of Baldwin IV and half-sister of Isabella I of Jerusalem, and mother of Baldwin V of Jerusalem.
Her grandmother Melisende had provided an example of successful rule by a queen regnant earlier in the century.
Athanasius I Gammolo
Athanasius I Gammolo was the Patriarch of Antioch, and head of the Syriac Orthodox Church of Antioch from 595 until his death in 631.
Athanasius was also the author of" The Life of Severus of Antioch", a biography of the first Syriac Orthodox Patriarch of Antioch.
Theodosius VI of Antioch
Theodosius VI( Abourjaily) of Antioch was Greek Orthodox Patriarch of Antioch from 1958 to 1970.
Baldwin V, Count of Flanders
Baldwin V of Flanders( c. 1012 – 1 September 1067) was Count of Flanders from 1035 until his death.
He was the son of Baldwin IV, Count of Flanders, who died in 1035.
Isabella of Ibelin (died 1315)
Isabella of Ibelin( died 1315) was the daughter of Baldwin of Ibelin( d. 1313), lord of Korakou, and of Marguerite de Giblet.
Baldwin of Antioch
Baldwin of Antioch (died September 17, 1176) was a Frankish knight and general in service of the Byzantine Empire during the Byzantine–Seljuk Wars.
His paternal lineage is contested, being identified by various historians either as the son of Raymond of Poitiers or Raynald of Châtillon and Constance of Antioch, and brother-in-law of Byzantine Emperor Manuel I Komnenos.
An ally of the Emperor in his battles against the Seljuk Turks, Baldwin was one of his most trusted advisors and the only one of Manuel's senior commanders "of Western origin".
He commanded the right wing of the Byzantine forces guarding the siege and baggage train, largely composed of Latin mercenaries, at the Battle of Myriokephalon on September 17, 1176.
Upon approaching narrow Tzibritze Pass, the Seljuks launched an attack on Manuel's marching troops.
Baldwin led a cavalry charge attempting to drive the Turks from the hills in a counterattack but was surrounded and killed together with all his men.
In "Byzantium: The Decline and Fall" (1996), English historian John Julius Norwich described the aftermath of Baldwin's death (taken from the Byzantine historian Choniates, whose comments are not always unbiased);
Asclepiades of Antioch
Asclepiades of Antioch was Patriarch of Antioch and martyr.
He succeeded Serapion as Patriarch of Antioch in 211.
He was given the title of martyr, due to the trials he endured during Roman persecution.
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.

Question: Who is Baldwin Of Antioch's paternal grandfather?
Answer: William IX