Oratorio dei Filippini is a complex of historic buildings built in the 17th century. It is considered one of the most outstanding works of Francesco Borromini. It is mainly famous for its five-axis, two-story southern facade. It is also home to the oldest public library in Rome, the Biblioteca Vallicelliana.
In the library, you can still admire beautiful oak shelves designed by Borromini. The corner of the oratory (in Piazza dell'Orologio) is decorated with a clock tower (also a work by Borromini).
The main body of the building is divided into five sectors, separated by pilasters. The façade is entirely made of brick. It was demanded by the principals - members of the Congregation of the Oratory of St. Philip Neri. They wanted the material to be modest, the facade could not compete with Chies Nuova.