A masterpiece of Roman baroque, this tiny building was the first church designed by Francesco Borromini. His clever design – which includes a play of convex and concave surfaces and a dome illuminated by hidden windows – cleverly transforms the small space into a place of light and beauty. Completed in 1641, it stands at the intersection known as the Quattro Fontane, named after the late-16th-century fountains on its four corners, representing Fidelity, Strength and the rivers Arno and Tiber.
Borromini also designed the cloister, accessed through a passageway to the right of the altar.