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Regio III - Insula I - Basilica Cristiana (III,I,4)
(Christian Basilica)

The Christian Basilica was discovered and excavated in 1939, by Guido Calza. He found a late-antique structure (opus vittatum, opus latericium, rubble masonry), built in and on top of pre-existing Trajanic structures (opus latericium and opus mixtum): a building with rooms around a small courtyard (M), rooms belonging to the Baths of the Christian Basilica (F, G, M), and shops flanking a north-west - south-east running side-street, leading to the Decumanus Maximus (the later rooms D and E). A marble statue of Fortuna was found in room C, a mensa ponderaria (a slab with cavities to check compliancy to standard weights) in room D.

Date of the building

Thea Heres has established that the last phases of the building belong to the fifth century. Most of the masonry of the basilica belongs to the first half and perhaps the first quarter of that century. The apse in room C was added a few years later. The capitals in the building were made around 420 AD.

Click here to open the plan published by Heres in a new window (Heres 1982, fig. 82).

Annalisa Gobbi reached different conclusions after research in the late 1990's. According to her the apses in rooms C and D are contemporaneous. She maintains that rooms A, B, F, G, and H were added later, when columns were also installed. She prefers a date in the fourth century. She also maintains that after the addition of the apses the building was a domus.

Click here to open the plans published by Gobbi in a new window (Gobbi 1998, Tav. II and III).


From the Decumanus vestibule A is reached (w. of entrance 3.48). The vestibule leads to a central nave (B). To the north-east of the nave are rooms F, G and H. These rooms originally formed part of the baths to the north-east: they had raised floors, suspensurae. In the entrance of each room are two columns and a marble threshold. On one of the columns in room F is the inscription:

VOLVSIANI V(ir) C(larissimus)

The column comes from the marble depot in the adjacent building, the Temple of the Ship Carpenters, where the same text was found on several columns. This Volusianus lived in the fourth or early fifth century AD.

The south-west wall of the nave has a row of five columns. In the north-west wall are a marble threshold and step, leading to room C, which is at a lower level. In this room an apse was built. In the apse are two semicircular wall-niches for statues (starting at 1.05, average h. 2.14, d. 0.72, w. 1.35). Their position is curious. They are not positioned on the axis of the room, the nave and the vestibule. Instead, they are on a diagonal axis, from the south corner of the room to the central point between the two niches. The floor of rooms B and C was not found by the excavators. They did find many marble fragments however. Clearly the building had been plundered.

A few steps lead from room C to a small room to the north-east, flanked by two more rooms. A door in the southern room leads to a Trajanic building with a courtyard, of which five rooms around courtyard M were preserved.

To the south-west of A and B is another nave (E) that was also reached from the Decumanus (w. of entrance 2.66). A door in the south-west wall leads to rooms of building III,I,5 (room N). To the north-west is room D, with an apsidal back wall. In the apse (w. 3.07) are three wall-niches (w. 1.35, 1.46 and 1.96, d. 0.48). The central one is rectangular, the flanking ones are semicircular. In each niche a basin and a hole for a water-pipe were found. A large basin (height c. 0.80) must have been standing in front of the niches, set against the entire apse. In the outside (outer wall) of the apse is a small rectangular wall-niche. In the south wall of the room is a small apse with a basin. The apses and niches had marble revetment. Between the two apsidal rooms D and C are four columns and a doorway.

In the south-eastern entrance of room D are two columns, supporting an architrave with an inscription. The architrave was found near the building. It fits perfectly on its present spot. It is made of two marble blocks and has a total length of 3.85. One of the blocks had been used as a threshold. Before that it carried an inscription. Traces of a single line, containing names, have been read on top:

[---]S ALEXANDER [---] AMMIVS [---] IGENIVS [---] V C [---] STINIANVS

On the side facing room E is an inscription, which Calza read and understood as follows:


Calza suggests that the first two letters of the second line are a mistake and should be neglected.

The inscription

In the first line of the inscription on the architrave the four rivers of paradise are mentioned (Genesis 2, 10-14). According to Ambrosius Christ was the source (fons) of the four rivers, and thus the source of eternal life: Erat fons qui inrigaret paradisum. Qui fons nisi dominus Jesus Christus, fons vitae aeternae sicut Pater? ... Et dividitur fons in quattuor initia: nomen est uni Phison ... et nomen secundo Geon ... et flumen tertium Tigris ... et flumen quartum Eufrates ... (De Paradiso 3, 13-14). The four rivers were likened by Christian authors to the four gospels, and were according to Calza also related to baptism: Has arbores rigat quattuor fluminibus id est evangeliis quattuor quibus baptismi gratia salutari et caelesti inundatione largitur (Cyprianus, Epistulae 73, 10; see also Augustinus, De Civitate Dei 13, 21).

According to Calza the (illiterate?) man who hacked out the inscription made a mistake at the beginning of line two: he started again with the word TIGRIS. The names of the four rivers are in the nominative, so sunt may be added, leading to the translation: "In Christ are Geon Fison Tigris Euphrates. Drink from the sources of the Christians".

Alternative translations are:

  • "Paradise rivers, take your (now) Christian sources in Christ!" (Von Gerkan).
  • "In Christ! Geon, Fison, Tigris, Euphrates. Take them as the sources of the Christian!" (Klauser).
  • "Come to the sources of the Christians, that are Geon, Fison, Tigris, and Euphrates" (Février).

A diagonal line to the right of the vertical line of the first T in the second line has suggested to Egger that it is an F, and he suggests FL(uminum) C(h)RI(st)IANORVM: "Geon, Fison, Tigris and Euphrates are in Christ. Use the water of the rivers of Christ". Burzachechi maintains that this diagonal line is an optical illusion, a shadow, so that the interpretation FL(uminum) (and PEREGRINIANORVM by Mercati) has to be rejected.

Burzachechi furthermore argues that the letters TI in the second line cannot be understood as an error. It would have been easy to remove the two shallow letters. Also the person who had ordered the inscription would never have accepted this embarrassing mistake. There is furthermore not enough space for the letters ST. The first word of the second line is TIGRI[N]IANORVM ("Use the sources of the Tigriniani"). Burzachechi suggests that the Tigriniani were either a Christian family or heretics, the followers of a certain Tigrinius or Tigrinianus. There may also be an allusion to the name of one of the four rivers in the first line, the Tigris.

Marrou points out that heretics are documented very well in ancient literature, but Tigriniani are not among them. He points to a priest named Tigrinus, who was active during the papacy of Leo I (440-461 AD). He oversaw the building of a church on the Via Latina. His funeral inscription states that he repaired sacred buildings: Diversis reparo tecta sacrata locis, culminaque hic lapsis trabibus totumque novendo, promerui superas laetior ire domos. The repairs may have been necessary after an earthquake in 442-443 AD. Parallels for the form Tigriniani are the Galbiani, Augustiani and Christiani, followers and supporters of Galba, Nero, and Christ.

However, Burzachechi's statement that the diagonal line making the first letter of the second line an F is in reality a shadow is not supported by photos. Old and recent photos show that the first letter of the second line is indeed an F. Egger is right. The confusion may have arisen from the very long horizontal line of the letter, perhaps intended to "connect" it with the monogram in the first line. Anyway, the correct reading is:

Geon, Fison, Tigris and Euphrates are in Christ.
Take the sources of the rivers of Christ.

Function of the building

According to Calza the building had in the final phase become a Christian church. He dates it to the period of Constantine and suggests that this is the church of Peter, Paul and John the Baptist that, according to the Liber Pontificalis, was donated to Ostia by Constantine. Calza then suggests, that the apsidal room behind the inscription was a baptisterium.

Calza's dating and interpretation of the building have been criticized by many authors. The building lacks many features of a basilica, such as the right nave and an altar, and the statue-niches in room C do not belong in a church. The basins are not suited for baptism, which required total submersion. Baptism was related to the river Jordan, not the rivers of paradise. Room D was a nymphaeum. And in the late 1990's the basilica of Constantine was located by Michael Heinzelmann, outside the Porta Laurentina.

The building was after Calza interpreted as:

  • A school for catechists (Von Gerkan).
  • A monument for a martyr (Février).
  • A library used by Christians (Klauser).
  • A xenodochium, that is, a guest house for pilgrims (Heres). Cf. the enlargement, in the fourth century, of the Ostian house (habitaculum) of Hilarinus, ad peregrinorum susceptionem.
  • Room D was a nymphaeum, made public by a Christian family, or used by heretics for an unorthodox baptismal ritual (Burzachechi).
  • A domus. Only the Chi-Rho monogram is Christian, the four rivers of paradise have no true Christian meaning, but are a parallel of Oceanus related to nymphaea in a pagan context (Brenk).

How the building can be seen as a domus is beyond the present author, who prefers the explanation offered by Heres, a guest house for pilgrims, albeit perhaps as modified by Santangeli Valenzani, who prefers to think of a general centre of assistance, especially for food. The rivers of paradise in line one are the rivers emanating from Christ in the form of the gospels and providing eternal life. There is an obvious link with the nymphaeum. The meaning is found if the building was a guest house for pilgrims who came to Ostia and of course Rome to visit the holy sites of the martyrs, or a place of assitance for the needy faithful: it was a place that provided water, food and perhaps a place to sleep.

Plan of the building. After SO I.

Photos and drawings

To the left room E and the architrave with the inscription, to the right nave B and room C, seen from vestibule A (the south-east).
Photo: Wikimedia.

Nave B and room C, seen from vestibule A (the south-east).
Photo: Amber Kreiensieck.

The room to the west of room M, seen from room C.
Photo: Tonino Menghi.

Room H, seen from the south-west.
Photo: Daniel González Acuña.

The niches in the apse of room D.
Photo: Daniel González Acuña.

The outer wall of rooms C and D.
Photo: Tonino Menghi.

Niche in the outer wall of the apse of room D.
Photo: Tonino Menghi.

The architrave with the inscription, seen from room E.
Photo: Jan Theo Bakker.

The inscription on the architrave.
Photo on site.

The left part of the inscription on the architrave.
Burzachechi 1959, fig. 4.

Detail of the inscription on the architrave.
Photo: Michele Mattei. Click to enlarge.

The inscription VOLVSIANI VC on a column in room F.
Photo: Eric Taylor.

A reconstruction drawing of the building, seen from the south.
Calza 1940, fig. 16.

A reconstruction drawing of the building,seen from the south. It is not certain that all rooms had a roof.
Calza 1940, fig. 17.

Room D, seen from the east, after the excavation. Centre left is the mensa ponderaria.
Brenk - Pensabene 1998, Taf. 19,1.

[jthb - 2-May-2022]