Purchased in 1811 by decision of the Brera Academy commission, made up of artists and scholars, the work was originally placed on the altar of San Sigismondo in the Malatesta Temple of Rimini, from which it was removed in 1581. The very high quality of the bas-relief testifies to the full maturity reached by Agostino di Duccio, when the Tuscan formation, between Donatello and Ghiberti, merges into a completely personal figure, dominated by a harmonious and elegant linearism. Carved in very low relief, the slab is dedicated to St. Sigismund, Christian king of the Burgundians, depicted during a pilgrimage made with his second wife to atone for the killing of his son. Agostino di Duccio represents the crucial moment in which an angel appears in the royal procession indicating the place in which to found the monastery of Agauno, today Saint-Maurice-en-Valais. The attitude of the angelic figure and the fluctuating rendering of the drapery recall the figurative characters of an ancient maenad, a tangible sign of the declared adherence to the classical language adopted by the Tuscan artist.