Acarius was a 7th-century monk from the Abbey of Luxeuil who eventually served as the Bishop of Doornik and Noyon. Born into a noble Burgundian family, he studied under Abbot Eustace and was a contemporary of Audomar. As a prominent advisor to King Clothar II, he played a significant role in expanding Christian influence throughout Belgic Gaul. He was known for his support of missionaries and his dedication to the welfare of the impoverished.