Austregisilus was a Frankish prelate born in Bourges around 551. After serving as an attendant to King Gontram at the court in Chalon-sur-Saône, he entered monastic life at the Saint-Nizier abbey. His ecclesiastical career included a period as an abbot in Lyon before he was elected as the Bishop of Bourges in 612. He is recognized as a significant religious figure of his era, having mentored Saint Amand and ordained Sulpitius the Pious.