Research Notes:

The Chronicle of Saint-Maixent names "Petrum cognomina Acerrimum et Gaufredum qui Wido vocatus est" as the twin sons of Duke Guillaume and his third wife Agnes. He adopted the name GUILLAUME, "Willelmus filii mei" being named in the charter of his mother Agnes dated 1031.

He succeeded his half-brother in 1039 as GUILLAUME VII "Acerrimus/l'Aigret" Duke of Aquitaine, GUILLAUME V Comte de Poitou, under the regency of his mother until 1044. Geoffroy II "Martel" Comte d'Anjou (formerly Duke Guillaume's stepfather) invaded Poitou in 1053.

"Aquitanorum…dux Gaufridus" confirms in his charter dated [1058/68] that "mea mater Agnes…frater meus Guillelmus" were both buried in the priory of Saint-Nicolas de Poitiers. ¹