San Carlo alle Quattro Fontane is a church dedicated to St Charles Borromeus and the Holy Trinity.
History
The church and monastery was built 1634-1638 by Borromini, and was the first church in Rome to be dedicated to St Charles Borromeus, who had been canonized in 1610. It was also the first church that Borromini built in Rome.
It belongs to the adjacent Spanish Trinitarian monastery, built by Borromini four years before he started work on the church.
The church is small, and the plan and proportions are said to be based on one of the piers supporting the dome of St Peter's. Because of its size, it is also known as San Carlino alle Quattro Fontane, Little St Charles' at the Four Fountains. The appellation refers to the four fountains at the corners of the intersection where the church stands.
Exterior
The travertine façade, completed by Borromini's nephew Bernardo in 1667 according to his uncle's design, is integrated with the monastery. It is on two levels. Above the doorway, a niche is crowned by a tympanon formed by the wings of two angels. Beneath the wings is a statue of St Charles Borromeus by E. Antonio Raggi. On the sides are statues of St John of Matha and St Felix of Valois, the founders of the Trinitarian Order.
Interior
The altarpiece, by Pierre Mignard, has a depiction of Sts Charles Borromeus, John of Matha and Felix of Valois.
The mummified body of a Roman soldier martyr lies in the chapel on the left side. The painting in the chapel is by Giovanni Francesco Romanelli, and depicts the Flight to Egypt.
A room outside the sacristy was set aside for Borromini's tomb, but it remains empty. The great architect committed suicide in 1667.
The refectory has a painting of St Charles Borromeus, painted by Orazio Borgianni in 1611. There are also beautiful stucco decorations.
Special notes
The church has often been closed recently. You may ask the sacristan, who you'll find by ringing the bell at the monastery door, to let you in. I suggest that you also ask him to show you the porcelain holy water stoup attributed to Borrimini, which is kept in the sacristy.