Margaret of Cortona (1247-1297) was the daughter of a peasant and for several years the mistress of a nobleman. On her lover's death she repented her sins and sought admission to the Franciscan Order. Gandolfi has represented her, as had many other baroque painters, wearing the knotted girdle of the Franciscan Order and kneeling before a crucifix accompanied by a little spaniel, her usual attribute, which belonged to her lover who was murdered after visiting her. The dog returned to Margaret and succeeded in leading her to its master's body.
No painting related to this drawing is known although a similar kneeling figure of the Saint holding a skull and accompanied by her dog appears in Gandolfi's 1775 altarpiece in the church of S. Giorgio, Porto San Giorgio, Ascoli Piceno (D. Biagi Maino, Gaetano Gandolfi, Turin, 1995, no. 94, pl. 110).