The chapel, recently built by a brigasque priest who had stayed in Rome, Guglielmo Alberti, was opened to worship in 1684. A 1730 cartouche commemorates the installation of the brotherhood, which would not be the origin of the construction.
The plan, close to the ellipse, is reminiscent of Baroque architecture type initiated by Bernini in Rome.
A wide front staircase serves the construction located on a slope next to the church.
Four pilasters punctuate the curved main facade, with an intermediate cornice simulating two levels. The central door, surmounted by a curvilinear awning decoration carries pot-a-feu. On each side large niches are located, they are covered with shell pattern vaults.
The nave has four bays. The extremities ones are rounded, one of them contains the altar and the other the main door. It is covered with barrel vaults separated by double arches.
The Altarpiece, in Rococo style stucco with cherubs, frames a canvas depicting the Annunciation, signed by Jacobus Rodi in 1611.
The sidewalls of the four bays, separated by acanthus pilasters, feature eight paintings depicting the miracles of Christ.
The arches of the spans are also painted in trompe l’oeil. Two allegories appear: above the Altar, the Intercession of the Virgin for the souls of Purgatory, on the entrance, a Virgin with the child.
The chapel houses the Collegiate’s Treasury Museum.