Whether the Roman basilicas, with which we are chiefly concerned, were derived directly from the Athenian example, or mediately from this through structures of the same kind erected in the later Greek cities, is hard to say. We should naturally look in that direction for the prototypes of the Roman basilicas, but as a fact we are not informed of any very early basilicas in these cities. The earliest we know of is the existing basilica at Pompeii, that may date back into the 2nd century B.C., whereas basilicas made their appearance at Rome nearly at the beginning of that century. The first was erected by M. Porcius Cato, the censor, in 184 B.C., and was called after his name Basilica Porcia. Cato had recently visited Athens and had been struck by the beauty of the city, so that it is quite possible that the importation was direct.Fig. 2. - Plan of Basilica Julia, Rome.
Rome soon obtained other basilicas, of which the important Basilica Fulvia-Aemilia came next in point of time, till by the age of Augustus there were at least five in the immediate neighbourhood of the forum, the latest and most extensive being the Basilica Julia, which ran parallel to its southern side, and is shown in plan in fig. 2. The great Basilica Ulpia was built by Trajan in connexion with his forum about A.D. 112, and a fragment of the Capitoline plan of Rome gives the scheme of it (fig. 3), while an attempted restoration of the interior by Canina is shown in fig. 4. The vaulted basilica of Maxentius or Constantine on the Via Sacra dates from the beginning of the 4th century, and fig. 5 gives the section of it. The number of public basilicas we read of at Rome alone amounts to about a score, while many private basilicas, for business or recreation, must also have existed, that in the palace of Domitian on the Palatine being the best known. In provincial cities in Italy, and indeed all over the empire, basilicas were almost universal, and in the case of Italy we have proof of this as early as the date of the death of Augustus, for Suetonius (Aug. 100) tells us that the body of that emperor, when it was brought from Nola in Campania to Rome, rested "in basilica cujusque oppidi."Fig. 4. - Interior view of Trajan's Basilica (Basilica Ulpia), as restored by Canina.
As regards existing examples, neither in the peninsula nor the provinces can it be said that these give any adequate idea of the former abundance and wide distribution of basilicas. Northern Africa contributes one or two examples, and a plan is given of that at Timgad (fig. 6). The Gallic basilicas, which must have been very numerous, are represented only by the noble structure at Trier (Trèves), which is now a single vast hall 180 ft. long, 90 ft. wide and 100 ft. high, commanded at one end by a spacious apse. There is reason to conjecture that this is the basilica erected by Constantine, and some authorities believe that originally it had internal colonnades. In England basilicas remain in part at Silchester (fig. 7), Uriconium (Wroxeter), Chester (?) and Lincoln, while three others are mentioned in inscriptions (C.I.L. vii. 287, 445, 965).
A comparison of the plans of existing basilicas shows considerable variety in form. Some basilicas (Julia, Ulpia, Pompeii) have the central space surrounded by galleries supported on columns or piers, according to the normal scheme, and the newly excavated Basilica Aemilia, north of the Roman forum, agrees with these. In some North African examples, in the palace basilica of Domitian, and at Silchester, there are colonnades down the long sides but not across the ends. Others (Trier [?], Timgad) have no interior divisions. One (Maxentius) is entirely a vaulted structure and in form resembles the great halls of the Roman Thermae. At Pompeii, Timgad and Silchester, there are fixed tribunals, while vaulted apses that may have contained tribunals occur in the basilica of Maxentius. In the Basilica Julia there was no tribunal at all, though we know that the building was regularly used for the centumviral court (Quint. xii. 5. 6), and the same was the case in the Ulpia, for the semicircular projection at the end shown on the Capitoline-plan, was not a vaulted apse and was evidently distinct from the basilica.
Fig. 5. - Section of the Basilica of Maxentius or Constantine (Temple of Peace).
In view of the above it might be questioned whether it is safe to speak of a normal form of the basilica, but when we consider the vast number of basilicas that have perished compared to the few that have survived, and the fact that the origins and traditions of the building show it to have been, as Vitruvius describes it, essentially a columned structure, there is ample justification for the view expressed earlier in this article. There can be little doubt that the earlier basilicas, and the majority of basilicas taken as a whole, had a central space with galleries, generally in two stories, round it, and some arrangement for clerestory lighting. Later basilicas might vary in architectural scheme, while affording the same sort of accommodation as the older ones.
The relation of the civil basilica of the Romans to the Christian church has been extensively discussed, and the reader will find the controversy ably summarized in Kraus's Geschichte der christlichen Kunst, bk. 5. There is nothing remarkable in the fact that a large church was called a basilica, for the term was applied, as we have seen, to structures of many kinds, and we even find "basilica" used for the meeting-place of a pagan religious association (Röm. Mitt. 1891, p. 109). The similarity in some respects of the early Christian churches to the normal form of the columned basilica is so striking, that we can understand how the theory was once held that Christian churches were the actual civil basilicas turned over from secular to religious uses. There is no evidence for this in the case of public basilicas, and it stands to reason that the demands on these for secular purposes would remain the same whether Christianity were the religion of the empire or not. Moreover, though there are one or two civil basilicas that resemble churches, the latter differ in some most important respects from the form of the basilica that we have recognized as normal.