Basilica of Saint Paul outside the Walls

Tradition places the burial of Paul of Tarsus in a plot on the Via Ostiense owned by a Christian woman named Lucina, with a tropaeum over the grave that drew veneration. Constantine the Great built a basilica on that site, consecrated by Pope Sylvester in 324.

From 386 Theodosius I began a far larger building, with a nave, four aisles and a transept. The Via Ostiense now lay to the east, and so the church was extended westward towards the Tiber, reversing the orientation. Its dedication is put at 390 under Siricius by some accounts and around 402 under Innocent I by others, and the mosaics were not finished until the pontificate of Leo I (440-461). After fire or lightning brought down the roof, Leo I raised the transept and installed an altar above Paul's tomb, and repaired the triumphal arch, whose mosaics an inscription records as paid for by Galla Placidia.

Under Gregory the Great (590-604) the transept pavement was raised again and a new altar placed directly over Paul's sarcophagus. An earthquake on 29 April 801 collapsed the roof, which Leo III rebuilt. As it lay outside the Aurelian Walls, the basilica was damaged during a ninth-century Saracen raid, and John VIII (872-882) consequently fortified the basilica, the monastery and the peasants' dwellings into a town called Giovannipoli, which existed until an earthquake destroyed it in 1348.

In 937 Alberic II of Spoleto entrusted monastery and basilica to Odo of Cluny's congregation, and Gregory VII was abbot here. Pantaleone, an Amalfitan merchant in Constantinople, gave the bronze doors, executed by Constantinopolitan artists. The cloister was finished in 1241, and Arnolfo di Cambio's ciborium dates to 1285.

Fire broke out on the night of 15 July 1823 and burned for some five hours. The official account blamed a workman repairing the copper gutters of the roof, who left alight the fire used for the job. More recent study has questioned the official cause. Alone among the churches of Rome, the building had kept much of its original character for 1,435 years.

The transept held, preserving much of Arnolfo's ciborium and some mosaics, and the apse, triumphal arch and cloister survived; Pietro Cavallini's fresco cycle in the nave was lost, and the bell tower was pulled down. Pius VII, who had fractured a femur on 6 July and was dying, was not told of the fire; he died on 20 August.

Leo XII's encyclical Ad plurimas of 1825 called for donations, and he ordered the church rebuilt exactly as it had been when new in the fourth century while keeping the medieval mosaics and tabernacle; those guidelines proved unrealistic, soon ceased to be enforced, and the rebuilt basilica bears only a general resemblance to the original. Pasquale Belli directed the work until his death in 1833, after which Luigi Poletti supervised it until his own death in 1869.

Gregory XVI consecrated the transept and high altar in October 1840 and that part reopened; Pius IX reconsecrated the whole church in 1854, but work ran on: the quadriporticus towards the Tiber was added in 1928 by the Italian government, which declared the church a national monument. An explosion at the Forte Portuense gunpowder magazine on 23 April 1891 shattered the stained glass, replaced by thin alabaster panes.

The basilica stands on Italian soil, but the Holy See owns it and it falls under Vatican extraterritoriality. It is the conventual church of the adjoining Benedictine abbey, one of Rome's four major papal basilicas and of its Seven Pilgrim Churches, and part of a UNESCO World Heritage listing; the Holy Door is opened only during Jubilees. Benedict XVI placed the basilica under an archpriest on 31 May 2005, and James Michael Harvey has held the office since 23 November 2012.

Excavation beneath the papal altar ran from 2002 to 22 September 2006, begun after pilgrims in the Jubilee of 2000 expressed disappointment that the tomb could not be visited or touched; a white marble sarcophagus was confirmed under the altar that December. In 2009 Benedict XVI announced that radiocarbon dating of bone fragments from it gave a first- or second-century date, though Ulderico Santamaria of the Vatican Museums' diagnostics laboratory cautioned that the dating neither confirms nor invalidates the traditional attribution to Paul. On 23 October 2025 Charles III, Supreme Governor of the Church of England, entered through the Holy Door and was made a Royal Confrater of the abbey at an ecumenical celebration led by its abbot, Donato Ogliari.