Wandregisilus (Latin Wandregisilus, French Wandrille) was a young Frankish Catholic noble of the Merovingian royal court who served in the court of King Dagobert I in the 620s and 630s. Around 635 AD — after a substantial spiritual conversion through contact with the great Irish-Frankish missionary tradition (he was substantially influenced by Columbanus's Luxeuil tradition; see Columbanus's entry already in the catalogue) — Wandregisilus renounced his court position and entered religious life.
After substantial monastic training at multiple early-Frankish monastic foundations (Montfaucon, Bobbio, Romainmôtier), Wandregisilus established around 649 AD his own Norman monastic foundation at the small Norman valley of Fontenelle in the Caux region of upper Normandy. The foundation became — across the 7th and 8th centuries — one of the continuous Norman monastic centres, producing substantial generations of Norman saints and serving as the Norman-Catholic intellectual-cultural centre.
Wandregisilus governed the Abbey of Fontenelle (renamed Saint-Wandrille after him) for nearly twenty years until his death on July 22, 668. The Abbey of Saint-Wandrille has continued in substantial operation (with interruptions during the Norse invasions of the 9th century and the French Revolution) for nearly 1,400 years and remains today a Norman-Catholic continuous monastic foundation. He is the father of the Norman Catholic monastic tradition.