Monica, the mother of Augustine, prayed for her son’s salvation. Augustine cherished his mother for her role in his conversion. By the time Piero painted this altarpiece, an image of Monica was required in every Augustinian church. The white scroll she unfurls is the order’s rule or code of conduct. Wearing a black cowl drawn at the waist with a leather belt, closed by a metal buckle, she is dressed as an Augustinian.