• Born: Abt 937, Aquitaine, France
• Married: Abt 968
• Died: 3 Feb 994, Saint-Maxient, Saint-Maixent-l'École, Deux-Sèvres, Poitou-Charentes, France
• Buried: Abbaye de Saint-Maixent, Saint-Maixent-l'École, Deux-Sèvres, Poitou-Charentes, France

  Research Notes:

The Chronicle of Adémar de Chabannes names "Willelmum" as son of "Willelmo Capite stupæ" when recording that he succeeded his father. "Ebulus…Lemovicensium sedis episcopus" donated property including "alodum…meum Baidon" to Saint-Maixent "pro remedio animæ…fratris mei Guillelmi, sive pro consolatione nepotism mei equivoci Guillelmi Aquitanorum ducis" by charter dated Jan [965/66].

He succeeded his father in 963 as GUILLAUME IV "Fier-à-Bras/Fera Brachia" Duke of Aquitaine, GUILLAUME II Comte de Poitou, lay abbot of Saint-Hilaire-de-Poitiers. "Guilelmus…Aquitanensium dux et cœnobii…Hylarii abbas" donated property to "clericus…Rodgarius" by charter dated Mar 967. "Wilelmus…Aquitaniensium dux et cœnobii…Hylarii abbas" donated property to "Mainardo", at the request of "patruus noster domnus Ebolus, sancte Lemovicensis sedis episcopus atque…beati Hylarii archiclavus", by charter dated Jan 969, subscribed by "Adraldo vicecomes, Arbertus vicecomes, Kadeloni vicecomes…" At first a powerful duke, he led a dissolute life after the departure of his wife, became increasingly ill and fell under the influence of Madelme, an Italian doctor, whom he rewarded with a vast estate near Fontenay. Duke Guillaume became increasingly religious following the return of his wife in 988, and under her influence the couple made donations to numerous religious establishments. "Guilelmus Aquitaniencum dux" founded a hospital near Saint-Hilaire de Poitiers by charter dated Jan 989, subscribed by "Emma comitissa, Guillelmi filium eius, Guilelmi comitis Engolismæ…" It appears that a reaction to these religious excesses set in, and the duke's wife left him once more together with their older son in 991.

Duke Guillaume abdicated in Jan 993 in favour of his son, and retired to the Abbey of Saint-Cyprien de Poitiers, later transferring to the Abbey of Saint-Maixent where he became a monk on his deathbed. ¹