Prior to the 17th-century, paintings of the Piazza depict a drab 12th-century Romanesque brick church of San Florenzio hemmed by tall medieval houses.
Once the oratory was complete in 1648, the Oratorians received a further endowment from the son of Senator Giuliano de' Serragli, who commissioned an additional church from the Baroque architect Pietro da Cortona.
The portals have triangular pediments with white marble sculptures of leaning allegories: Faith and Hope with putti holding aloft the Sacred Heart, sculpted by Giovacchino Fortini in the church, while Prayer and Humility with putti holding a star, sculpted by Pompilio Ticciati and Giovanni Nobili (sculptor) grace the Oratory.
[7] The Chapel of the Madonna has a Virgin by Carlo Maratta and an Eleven Thousand Martyrs by Stradanus, which had been in the earlier church of San Firenze.
Other paintings in the church are by Giuseppe Pinzani, Tommaso Redi, Antonio Puglieschi, Anton Domenico Gabbiani, S and G Perini.
The ceiling of the oratory, designed by Silvani has a canvas of Giovanni Camillo Sagrestani depicting the Glory of St Phillip.