The altarpiece is a representation of the conceptual hypothesis of the founding of the Church on the rock of Saint Peter and apostolic succession. To the left of Saint Peter, patron saint of the church where the painting originally hung, is a reading Saint Mark the Evangelist, whom, according to tradition, Saint Peter asked to evangelise the metropolitan see of Aquilea; to the right, behind Saint Paul, is the bishop Titian of Oderzo (sixth–seventh century), patron of the diocese of Ceneda, to which the parish church of Fontanelle from which the work comes belongs.

The two female saints on either side of the cathedra, who are distinguished solely by the palm branch of martyrdom, have traditionally been identified with Justina of Padua (third–fourth century) and Augusta (fifth century), both martyrs for the faith. The painting dates from the first half of the ’20s, just before the Saint Barbara Polyptych in Santa Maria Formosa in Venice, and demonstrates the artist’s dependence on models derived from Titian in composing the scene and in the felicity of his colour scheme.