The cycle of paintings in the Portinari Chapel was carried out between 1462 and 1468 by Vincenzo Foppa. The main scenes portrait the Annunciation, on the wall in front of the entrance; the Assumption of the Virgin, on the opposite side; the Miracle of the healed foot and the Martyrdom of Saint Peter Martyr, on the left wall; and the Miracle of the cloud and the Miracle of the false Madonna, on the right wall.
The choice of depicting scenes of the life of the Virgin Mary is explained by the fact that the Dominican friars were great promoters of the Marian devotion. Typical features of the Order of Preachers’ activity also included attention to teaching and simple storytelling, as well as the selection of emblematic episodes of the life of Saint Peter Martyr – three miracles were chosen in addition to the martyrdom scene, highlighting the moment when the saint, already fatally injured, reasserts his faith by writing I believe with his own blood. The first miracle portraits the saint as a wonderworker (the Miracle of the healed foot), while the two scenes on the right wall are linked to the events of the fight against Catharism. Actually, in the Miracle of the false Madonna, Saint Peter Martyr reveals the deceit of a Cathar who had persuaded devotees to worship a false Madonna, whose horns are proof that she is sent by the devil. The other scene under the same arch tells an episode occurred in the square right in front of the Basilica of Sant’Eustorgio – Saint Peter made a rain-bearing cloud appear to provide some cooling to the worshippers who had come to listen to the saint.

The iconographic setting is completed by the decoration of pendentives with oculi, inside which the four Fathers of the Church (Saint Gregory the Great, Saint Jerome, Saint Ambrose and Saint Augustine) are portrayed, and by the lower portion of the dome, where eight busts of saints look out just as many oculi.