[a] His parentage is unknown but by his name he was associated with Creil, a small town in the territory belonging to Bernard, Count of Senlis.
[1][2] In 942 his actions helped save the life of Richard, Duke of Normandy, who was effectively held a prisoner by King Louis IV of France at Laon.
[3] Yves de Creil learned of the plot and passed the information to the boy's tutor, Osmund, who then took Richard secretly to the safety of the castle of Coucy, held by Bernard of Senlis.
In a diploma of St. Dennis dated 18 March 968 a signatory is an Ivonis whom Stapleton identifies as Yves de Creil.
[6] Another charter by Hugh, Archbishop of Rouen to abbot Galon of Abbey of Saint-Germain-des-Prés (979-89) contained, among the attesters, "S. Ivonis, Item S. Ivonis" who Prentout thought to be Yves de Creil and his son Yves de Belleme.