The altarpiece, Giacomo Cavedone’s most famous work, shows the basic components of the painter's style, which brings together Carracci’s naturalist research and the suggestions of sixteenth-century Venetian painting.

The monumental painting was made in 1614, commissioned by the Confraternity of Blacksmiths, for the church of Santa Maria della Pietà, known as dei Mendicanti, in Bologna.

In the foreground, kneeling in the act of worshiping the Virgin and Child, supported by clouds and angels, are the Saints Eligius, patron saint of blacksmiths and Petronius, patron saint of the city of Bologna, whose medieval towers loom in the distance against a stormy sky.

St. Alò, the popular name of St. Eligius, is dressed in an ochre and blue artisan’s outfit and is accompanied by the usual blacksmith's tools scattered around his feet, while St. Petronius is celebrating mass and looks up from the great missal supported by the genuflecting acolyte. Behind him, one of the two young men holding the pastoral staff is looking toward the observer.

While the Madonna and Child is based on models by Titian, St. Petronius’ pose is splendidly reminiscent of the pose of the client in the Bargellini Altarpiece, which can be viewed in Room 23, a work by Ludovico Carracci of whom Cavedone was a pupil.