Guillaume le Gros, VI duc d'Aquitaine et comte IV de Poitiers

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Guillaume 'le Gros' de Poitou, VI duc d'Aquitaine et comte IV de Poitou

Birthdate: (34)
Death: December 15, 1038 (34)
Place of Burial: Maillezais, Pays de la Loire, France
Immediate Family:

Son of William V, duke of Aquitaine and Almode de la Marche, Contess of Charroux
Husband of Eustachie de Montreuil
Father of Marguerite de Poitou, dame de Saintes and Inés de Aquitania
Half brother of Beatrix of Poitou; Guillaume VIII (Guy Geoffrey) d'Aquitaine, VIII duc d'Aquitaine et Vl comte de Poitou; Pierre Guillaume 'l'Aigret' ou 'le Hardi' d'Aquitaine, VII Duc d'Aquitaine, V Comte de Poitou; Agnes of Poitou; Adèle (Adélaïde) d'Aquitaine and 8 others

Occupation: Duke of Aquitaine and Count of Poitou (as William IV) between 1030 and his death
Managed by: Private User
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About Guillaume le Gros, VI duc d'Aquitaine et comte IV de Poitiers

Son of Guillaume and his first wife, Adalmode. One of THREE sons who became Guillaume Duke of Aquitaine.

Foundation for Medieval Genealogy:

GUILLAUME de Poitou ([1004]-15 Dec 1038, bur Maillezais, Abbaye de Saint-Pierre). Ademar names "Willelmum" son of "Willelmi ducis" by his previous wife before he married "Briscam"[365]. "Willelmi ducis Aquitanorum, Willelmi filii eius, Odoni filii eius, Prisca comitisse" subscribed the charter dated to [1012/18] under which "Ugo Liziniacensis domnus" donated property to St Cyprien, Poitiers[366]. "Willelmi comitis et abbatis, eius filii Willelmi…Odonis…" subscribed the charter dated 3 Aug 1016 under which "Guilelmus…dux Aquitaniensium" granted rights to Saint-Hilaire de Poitier[367]. His father refused on his behalf an offer of the throne of Italy in 1025 made by rebels against Konrad II King of Germany[368]. "Willelmus Pictavorum comes et dux Aquitanorum…filius Guillelmi comitis" donated property to Saint-Maixent by charter dated [1023/26] subscribed by "Willelmi comitis, Willelmi patris eius"[369], the order of names in the subscription suggesting that some sharing of power took place between Duke Guillaume V and his son before the death of the former.

He succeeded his father in 1029 as GUILLAUME VI "Pinguis/le Gros/le Gras" Duke of Aquitaine, GUILLAUME IV Comte de Poitou, de Saintonge and de Guyenne. The Chronicle of Saint-Maixent records that "Guillermus Pinguis filiorum eius maior natu" succeeded his father[370]. Geoffroy "Martel" d'Anjou (married to Duke Guillaume's stepmother) declared war on Poitou. At the battle of Mont-Couer 20 Sep 1033, he captured Duke Guillaume who was released end-1036 following the intervention of his wife on payment of a large ransom[371]. It is incorrect, as stated by William of Malmesbury, that Duke Guillaume survived his release by only three days[372]. Rodolfus Glaber records the death of "Willelmus…Pictavorum comes" in the same year as Emperor Konrad II [1038], recalling that he had been released and sent home for a great ransom three years after his capture in battle by Geoffroy Comte d'Anjou[373]. The Chronicle of Saint-Maixent records that "Guillermi Comitis" (husband of Eustachie) was buried "cum patre apud Malliacum"[374].

m (before 20 Jul 1031) EUSTACHIE, daughter of --- (-after 1038, bur Notre Dame de Poitiers). "…Willelmi comitis, Eustachie…" subscribed a charter dated 1030 or 1031 under which "Raingardis" donated property "in pago Pictavo et in vicaria Ygrandinse in villa…Targiacus" to St Cyprien[375]. Eustachie is named with her husband in the records of a lawsuit while Robert I King of France still reigned[376]. "…Willelmi comitis Pictavensi…Eustachiæ comitissæ, Alæ comitissæ sororem Willelmi comitis" subscribed a charter dated 5 Dec [1031/33] under which "Willelmus Engelbertus et Willelmus filius Ansemi, nomine Lambertum, et sororem eius…Abba" donated property to Saint-Maixent[377]. "Eusthacia comitissa per mandatum domni mei Willelmi ducis" who was "positus in captione" donated property to Saint-Maixent by charter dated [1033/36] subscribed by "domni Willelmi comitis [despite his absence in captivity] Eustachiæ comitissæ, domni Hisemberti, Ala comitissæ…"[378]. Eustachie's origin is unknown. According to Richard, the theory that she was Eustachie de Montreuil, daughter of Berlay [III] de Montreuil & his [first] wife --- is unsupported by primary sources[379]. The same author emphasises that, if the Montreuil origin is correct, Eustachie could not have been the daughter of Berlay [III]'s wife Grace, who married secondly in [1052] Geoffroy II "Martel" Comte d'Anjou, while "still young", but he does not cite his source for this last observation. The Chronicle of Saint-Maixent records that "Eustachia uxore Guillermi Comitis" was buried "apud S. Mariam Pictavis"[380].

Duke Guillaume VI & his wife had [one possible] child:

a) [AGNES de Poitou . Agnes was the daughter of Duke Guillaume VI according to Szabolcs de Vajay, although he cites no source in support of this[381]. According to Richard, Duke Guillaume VI died childless[382]. Agnes is shown as the possible daughter of Duke Guillaume VII "l'Aigret" in Europäische Stammtafeln[383], marrying Pierre I Comte de Savoie as her second husband although she would have been only about six years old at the time of her supposed first marriage with Ramiro King of Aragon. From an onomastic point of view, it is surprising that a daughter of Duke Guillaume VI would have been named Agnes, a name which appears to have been introduced into the family of the Comtes de Poitou only after the third marriage of Duke Guillaume V to Agnes de Mâcon. The primary source which confirms her marriage to King Ramiro has not yet been identified. m ([1054]) as his second wife, RAMIRO I King of Aragon, illegitimate son of SANCHO III King of Navarre & his mistress Sancha de Aibar (Aibar [1008]-killed in battle Graus 8 May 1063, bur Monastery of San Juan de la Peña).]

William VI (1004 – March 1038), called the Fat, was Duke of Aquitaine and Count of Poitou (as William IV) between 1030 and his death. He was the eldest son of William V the Great by his first wife, Adalmode of Limoges.

Throughout his reign, he had to face the hostility of his stepmother, Agnes of Burgundy, the third wife of his father, who had remarried to Geoffrey Martel, then count of Vendôme. He entered into a war with Martel, who pretended to the government of the Saintonge. On 20 September 1034, he was captured in the field at Moncontour, near Saint-Jouin-de-Marnes. He was freed in 1036, after nearly three years imprisonment, only by ceding the cities of Saintes and Bordeaux. He immediately reopened the war, but was defeated again and had to cede the isle of Oléron.

William married Eustachie of Montreuil but had no known descendants. He reformed the administration of Poitiers by naming a provost and died there, being buried at Maillezais, being succeeded by his half-brother Odo.

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Guillaume le Gros, VI duc d'Aquitaine et comte IV de Poitiers's Timeline

Age 21
December 15, 1038
Age 34
Age 34
Count of, Poitou, , France
Maillezais, Pays de la Loire, France