Thanks to the old inscription, it is possible to identify the design as that of Muziano´s lost painting, formerly in the sacristy of S. Agostino, Rome. The drawing thus preserves a visual record of the composition of this lost picture. St. Monica was the mother of three children, the eldest of whom was St. Augustine, the future Doctor of the Church. At the end of her life, she followed him to Rome and died at Ostia in 386 on her way to Africa with him. Her relics are preserved in S. Agostino.

Turner, Nicholas, From Michelangelo to Annibale Carracci. A century of Italian drawings from the Prado, Chicago, Art Services International, 2008, p.320