The Chapel of Mercy was rebuilt at the same time as the church of Santa Maria in Albis, at the end of the 17th century.
The facade decoration of the chapel, made in the early eighteenth century, has a Baroque refinement that is more precise than other contemporary buildings’ in the town. Double and triple pilasters as well as large cornices structure it in three zones of decorations on three levels.
- At the base, the door is surrounded by fluted columns leaning against a curved broken pediment (interrupted). This entrance (scrolls dominating it) as well as the arched pediments of the lateral niches of the second level remain marked by a post-Renaissance classicism.
- The top of the second level further develops the baroque ornamentation of the time by its scrolls and Corinthian inspiration capitals. A rococo cartridge surmounts the triple window.
- The narrower third level is surrounded by volute fins and obelisks (one was dismantled after the war). The sacred heart of Jesus figured in the central medallion is overlooked by the pediment that houses the eye of Providence in the radiating triangle, common symbol of the Trinity found on chapels of that time.
Bulb-glazed tiles in scales surmount the southern side pinnacle, created between 1880 and 1890.
A square-shaped choir extends the single nave. On the other side, at the entrance, stands a platform. The classical stucco decorations of the 18th century, pilasters with capitals and perimeter cornice, as well as the more baroque inspired altarpiece are still complete and in fairly good condition. Accessible from the grandstand, a walk on the cornice goes around the room.
The frescoes of the vaults of the nave and the choir, made at the end of the 19th century, are trompe-l’oeil and stenciled geometric decorations, but also a scene of the takeoff of Saint-Jean Baptiste in the nave and the four evangelists in the choir.