The much restored church of Santi Giovanni e Paolo (Saints John and Paul) was founded at the beginning of the fifth century. The dedication is to two obscure court officials who are said to have been martyred under the emperor Julian the Apsotate (r. 361-63) and the church, which was rebuilt by Pope Paschal II (r. 1099-1118), stands on the site of their house.
The portico, which comprises eight ancient columns, was added in 1158. The inscription reads: PRESBITER ECCLESIE ROMANE RITE JOHANNES HEC ANIMI VOTO DONA VOVENDA DEDIT MARTYRIBVS CHRISTI PAVLO PARITERQVE IOANNI PASSIO QVOS EADEM CONTVLIT ESSE PARES (John, a priest of the church of the Roman rite, by a willed vow gave gifts promised to the martyrs of Christ, Paul and with him John, those who shared the same suffering).
The tall Romanesque red brick bell tower, forty-five metres in height, was completed circa 1150. It is in an odd position, as it reused the ancient masonry of part of the ancient Temple of the Divine Claudius.
The exterior of the church's apse is very impressive. The fabric is 5th century, but the present appearance is a result of a 13th century restoration. Such a decorative apse is unique in Rome. The fresco in the conch of the apse depicts Christ in Glory (1588) and is the work of Niccolò Circignani, better known asIl Pomarancio.
The interior of the church was restored at the beginning of the 18th century. A tomb-slab in the nave commemorates the burial place of the two martyrs, whose relics are preserved in an ancient porphyry bath under the high altar. The altarpiece depicting the Martyrdom of St John and St Paul (1726) was painted by Giacomo Triga.
Off the south aisle stands the large 19th century chapel of St Paul of the Cross, founder of the religious order known as the Passionists. The chapel houses the saint's relics.
Santi Giovanni e Paolo is the mother church of the Passionists.