The painting depicts Saint Catherine of Siena, a Dominican Tertiary, kneeling. The nun is with stigmata, wearing Dominican clothing: a white habit and a black cloak. Catherine of Siena (1347–1380) was a saint and an important political figure during the difficult times of the Avignon Papacy. Catherine was an illiterate daughter of a fabric dyer from Siena. Later, she achieved significant influence and corresponded with dukes, rulers, cardinals, and popes, although the saint received assistance in writing the letters. Catherine had many followers who called her "dolce mamma" (Italian for "sweet mother"). It was Catherine of Siena who contributed to the reconciliation between Florence and the Pope, as well as the return of the Pope from Avignon to Rome. Saint Catherine was part of the Dominican Mantellate and regularly visited the Santa Maria della Scala hospital, where she cared for the sick, treating the most difficult cases. During the plague, Catherine fearlessly assisted the afflicted and, when necessary, dug graves herself. On her body, she bore stigmata, but they remained invisible until her death. Saint Catherine of Siena passed away at the age of 33.