• Born: 1099, Toulouse, Haute-Garonne, France
• Married: Before 1122, France
• Died: 9 Apr 1137, Santiago de Compostela, Galicia, Spain
• Buried: Santiago de Compostela, Galicia, Spain

  Research Notes:

The Chronicle of Saint-Maxence records the birth in 1099 of "Willelmo comiti…filius æquivoce Guillelmus". William of Tyre names him and his father. Robert of Torigny names "Guillermum…pater…Alienor reginæ Anglorum" as the son of "Guillermus comes Pictavensis et dux Aquitanorum" & his wife "filia [comitis Tolosani fratris Raimundi comitis Sancti Ægidii]".

He succeeded his father in 1126 as GUILLAUME X Duke of Aquitaine, GUILLAUME VIII Comte de Poitou. “Willelmus...dux Aquitanorum” donated “ecclesiam S. Juliani de Stapio...ecclesiam S. Mariæ de Clida” to Notre-Dame de Saintes “et abbatissæ Sibillæ amitæ meæ” by charter dated “XII Kal Sep”, signed by “eadem abbatissa Sibillla, et comitissa Tholosæ avia mea, et Agnete amita mea...Petro episcopo...”. This charter does not specify the year but can be dated to [1126/27], given that Guillaume X Duke of Aquitaine (identified as the donor) succeeded his father in 1126 and that the successor of Pierre Bishop of Saintes (assuming that he can be identified as the subscriber “Petro episcopo”) is named in a document dated 1127. “Guillelmus comes Pictaviensis et dux Aquitanorum” confirmed rights of “monachi Monasterii Novi Pictaviensis” granted by “Gaufredus avus et Guillelmus pater mei” by charter dated 1129. “Willelmus…dux Aquitanorum” donated property to “ecclesiæ B. Hilarii de Cella” (La Celle, outside Poitiers) by charter dated 3 Mar 1130, subscribed by “Willielmi ducis Aquitanorum, Aenordis comitissæ, Alienordis filiæ eorum, Wilelmi Aigres filii eorum”.

The Chronique de Guillaume de Nangis records in 1136 that "Guillaume comte de Poitou et prince d'Aquitaine" died while on pilgrimage at "Saint-Jacques…la veille de Pâques" and was buried there. The necrology of the Prieuré de Fontaines records the death "28 Mar" of "Willelmus dux Aquitanorum". ¹