In about 56 CE, Saint Paul the Apostle wrote his famous Epistle to the Romans. At the time he was probably in Corinth. In the letter, he told his readers that he had plans to travel to Spain and that he wanted to visit Rome on the way, as he had not had the opportunity yet to visit the young Christian community there (Romans 15:22-24). If Saint Paul had travelled to Rome by his own free will, he would probably have disembarked at Ostia. However, things took a different turn. Paul was arrested in Jerusalem and, perhaps in 59 or 60 CE, sent to Rome as a prisoner for his appeal to the emperor Nero (he was, after all, a Roman citizen). After a shipwreck near Malta, a ship from Alexandria took the Apostle to Italy. But the ship did not dock at Ostia. Saint Paul landed at the great port of Puteoli in Campania and travelled to Rome by road from there. After dying a martyr’s death in about 67 CE, the Apostle was buried in a cemetery on the Via Ostiense, the road to Ostia. This is where we nowadays find the splendid basilica of San Paolo fuori le Mura. And yet in spite of the fact that Saint Paul found his final resting place near Ostia, there is a fair chance that he never actually visited the port of Rome itself.
Ostia certainly must have had a Christian community early on. As a cosmopolitan city with links to practically all regions of the vast Roman Empire, it was home to people of all kinds of cultures and religions. Other apostles must have tried to spread the new faith among members of the city’s Jewish population as well as among people who followed the traditional Roman cults. Saint Quiriacus of Ostia is traditionally counted as the first bishop of Ostia. He was said to have been martyred during the reign of Severus Alexander (222-235), but virtually nothing is known about his life. Those visiting the excavations of Ancient Ostia may want to take a look at the ruins of a small late fourth century oratory which was dedicated to him. These can be found just east of the theatre of Ostia and are very easy to miss (the oratory was truly tiny).
If Ostia indeed had a bishop by 230 CE, it must have had a building that was designated as the city’s cathedral. We do not know where this “cathedral” was. It certainly was not the small oratory that replaced a mithraeum near the so-called Baths of Mithras. If you buy a plan of Ostia at the ticket office, you may notice a building on the long decumanus maximus that is labelled “Cd Christian Basilica”. Do not be fooled: ‘Cd’ is the abbreviation of cosidetto, the Italian word for ‘so-called’. It is highly unlikely that this edifice was ever a Christian place of worship. It may have been a private residence (domus), but even this is far from certain.
In about 330, during the reign of the emperor Constantine the Great (306-337), a large basilica was erected just within the walls of Ostia which then almost certainly became its cathedral (its new cathedral if it already had one). This Constantinian Basilica stood in the south-eastern corner of the city and must have been over 51 metres deep and at least 23 metres wide. Virtually nothing of it remains today. The foundations of the basilica are located outside the visitable parts of the archaeological terrain anyway, so do not bother looking for them. If you are interested in Christianity in Ostia, visit the cathedral of Sant’Aurea instead. This cathedral can be found in the small medieval village to the east of Ancient Ostia which is rather confusingly called Ostia Antica.
The port of Ostia flourished from the first until the third century CE. Then came a long period of decline and recession. In the early Middle Ages, the city was particularly vulnerable. In 846, Muslim raiders from North Africa reached Ostia, sailed up the Tiber, sacked the San Paolo fuori le Mura and even stole the silver from the doors of Old Saint Peter’s Basilica. Three years later, the Muslims tried again, but they were defeated by a Christian coalition at the naval Battle of Ostia. Ostia was abandoned not long after that battle. The number of inhabitants had already dwindled, and whoever was left moved to the fortified village of Gregoriopolis, an old suburb of Ostia which had been strengthened by Pope Gregorius IV (827-844). The name Gregoriopolis apparently did not stick, and the village simply took on the name of the old and abandoned city just a little to the west of it. Its cathedral is therefore known as the Sant’Aurea a Ostia Antica. Modern Ostia is actually located directly on the coast and is known as Lido di Ostia.
The cathedral we see today dates from the fifteenth century and constitutes a rebuilding of an older cathedral. Driving force behind the new cathedral was cardinal Guillaume d’Estouteville (ca. 1412-1483), although the building was actually completed by cardinal Giuliano della Rovere (1443-1513), who later became the notorious Pope Julius II. The architect involved was presumably Baccio Pontelli (ca. 1450-1492), whose work we have seen previously (here and here). Pontelli may also have built the triangular castle to the west of the cathedral, which is called the Castello di Giulio II in Italian, after the aforementioned Pope Julius II. The castle allowed the Della Rovere family to control access to the river Tiber, but it may also have been intended as a precautionary measure against a possible Turkish attack on Rome (the Ottomans had captured Otranto in Southern Italy in 1480 and had slaughtered 813 of its citizens).
The Sant’Aurea is anything but spectacular (see the images included in this post). It is a simple rectangular box that lacks notable decorations. The cathedral is dedicated to Saint Aurea, a third century virgin martyr from Ostia whose historicity is a bit doubtful. If we go inside the building, we can find her depicted in the altarpiece, which is a painting by Andrea Sacchi (1599-1661). The real reason to visit this basilica is the Chapel of Saint Monica on the right. She was the mother of Saint Augustinus of Hippo (354-430), the famous theologian and church father. In 387, Augustinus had been baptised in Milan by Saint Ambrosius (see Milan: Sant’Ambrogio and Milan: The Duomo). His mother had tracked him down there. On the way back to Africa, she died in Ostia that same year. Monica was buried in Ostia, but her relics are no longer in the Sant’Aurea. These were moved to the church of Sant’Agostino in Rome in the fifteenth century. What we do find in the Chapel of Saint Monica is part of the fairly long epitaph from her tomb slab. The surviving text reads:
“HIC POSVIT CINE[RES GENETRIX CASTISSIMA PROLIS]
AVGVSTINE TV[IS ALTERA LVX MERITIS],
QVI SERVANS P[ACIS CAELESTIA IURA SACERDOS]
COMMISSOS PO[PVLOS MORIBVS INSTITVIS.]
GLORIA VOS M[AIOR GESTORVM LAVDE CORONAT]
VIRTVTVM [MATER FELICIOR SVBOLE].”
Which translates as:
“ Here the most chaste mother of her offspring placed her ashes, a second light, Augustine, for your merits. You, as a priest keeping the heavenly laws of peace, teach with your conduct the peoples entrusted to you. The glory of your virtues, greater than praise of your deeds, crowns you both, mother more fortunate in your offspring.”
The tomb slab was discovered in 1945 in the vicinity of the basilica. This suggests that the building that the current Sant’Aurea replaced in 1483 was already a Christian church by the year 387.
 Translation by Douglas Boin, as quoted by E. Gillian Clark in Monica: An Ordinary Saint, p. 164. There appear to be small variations in the Latin text, depending on the source.