The church had its beginning as a simple oratory added to a family villa suburbana of Pope Gregory I, who converted the villa into a monastery, ca. 575-580. The faca̧de and forecourt added by Soria (1629-1633) is the most complex of his designs. The square façade, two storeys high, is three bays wide and fronts an atrium leading to the church proper. Built at Cardinal Borghese's expense. Three uniform arched openings, surmounted by Borghese eagles, pierce the lower storey; the facade uses both Ionic and Corinthian orders. Francesco Ferrari (1725-1734) designed the interior.