Church of SS. Prospero and Filippo and Biblioteca capitolare fabroniana:

Erected in the 12th century, this church is dedicated to St. Prospero; it was remodelled in 1622 for the Rospigliosi family and in 1666 was brought under the order of the Oratory of St. Philip Neri. It has frescoes by Gian Domenico Ferretti and Lorenzo del Moro, painted after the building was made higher to accommodate the Library (1730-31). Created in 1726 from the book collection bequeathed by Cardinal Agostino Fabroni (Pistoia, 1651 - Rome, 1727), it contains around 14,000 printed and handwritten books on theological, humanistic and scientific subjects. The large reading room still has the original furnishings. To the sides of the entrance, on the first floor, are two important 18th-century marble sculptures by Agostino Cornacchini.