Other names for Petronille were Aelith and Petronilla.
Eleanor of Aquitaine the Mother Queen, Desmond Seward, 1978, Dorset Press, p18:
p18: "Very little is known of Eleanor's mother, Aenor. She was the daughter of the viscount of Chatellerault and his wife Dangerosa- William IX's concubine, the `Maubergeonne'. Aenor had three children: William Aigret (who died when still a boy), Eleanor of Aquitaine and Petronilla (who is sometimes called Aelith)..."
A History of the Plantagenets, Vol I, The Conquering Family, Thomas B Costain, Doubleday & Co, Garden City, 1949, p37:
"Duke William ruled Aquitaine and he was very old. He had one son who had gone to the Crusades and who was so good that the people called him St. William. The old man had not been a saint by any means but had spent a large part of his life wandering up and down his broad domain looking for romance, and always finding it. He now wanted to abdicate and spend his last years as a pilgrim and penitent, having in full degree that fear of the hereafter and the torments of hell which motivated so much of what happened in those days. His saintly son had two daughters only, Eleanor and Petonille, both of whom took after their grandfather."
Petronille married Raoul VERMANDOIS.