The ciborium above the high altar by Arnolfo di Cambio is dated 1285 and inscribed hoc opus fecit arnulfus cum suo socio petro. The ciborium was donated by Abbot Bartolomeo, who is shown presenting St Paul with a model of the ciborium in the spandrels of the western arch. The Gothic canopy is supported on antique porphyry columns and is richly ornamented with superb foliate capitals, small corner statues in a classicizing style, relief figures and Cosmatesque mosaic decoration .

Almost totally rebuilt after a fire in 1823. In addition to the standard basilicas, several major buildings were erected or decorated in Rome in the 5th century that exhibit a classicizing style and have thus been identified as part of a renaissance of Classical Roman architecture launched by Pope Sixtus III (reigned 432-440): these include S Paolo fuori le mura as decorated under Pope Leo I (reigned 440-461). The cloister dates from ca. 1205-1241. The Cosmati (traditional name for the marbleworkers of Rome (marmorarii Romani) active in the 12th and 13th centuries) produced cloisters of great beauty in the late 12th and 13th centuries, including S Paolo fuori le Mura.