Ansegisus was a Frankish monastic reformer who lived from approximately 770 to 833. Born into a noble family in Lyon, he joined the Fontenelle monastery at eighteen. Throughout his career, he held several significant leadership roles, including serving as the abbot of Luxeuil Abbey and returning to lead Fontenelle. He is recognized for his successful efforts to reform various religious houses under the patronage of Frankish rulers like Charlemagne and Louis the Pious.