Her eldest son Juhel III de Mayenne [Wikidata] was a celebrated Crusader.
Her father was a powerful Norman magnate with much wealth and political influence.
In 1161 Isabelle married her first husband, Geoffroy, Seigneur de Mayenne whose first wife Constance of Brittany had died in 1148.
Isabelle, aged about twenty-two, married secondly in 1170 Maurice II, Sire de Craon, the son of Hugues I, Sire de Craon.
The Gesta Guillelm Majoris Andegavensis Episcopi names Isabelle among those present at the burial of the Bishop Guillaume on an unknown date during the reign of King Philip II of France.