The apse itself has four round-headed windows on the outside, separated by Corinthian pilasters in shallow relief which support an entablature. The front of the apse has no window, but instead an epigraph detailing the restoration by Pope Clement X. Above is his coat-of-arms, borne by angels. The roofline has a pin balustrade with plinths for five statues by Francesco Fancelli, a local Roman sculptor. This set is his major surviving work. King David and SS Peter, Paul and Dominic are represented.