There is probably no basilica actually standing which was built during the reign of Constantine, or near his time; but there are several basilica churches in Rome, such as that of San Clemente, which were founded near his time, and which, though they have been partially or wholly rebuilt, exhibit what is believed to be the ancient disposition without modification.
Fig. 156.—Interior of a Basilica at Pompeii.
Restored, from descriptions by various authors.
Access is obtained to San Clemente through a forecourt to which the name of the atrium is given. This is very much like the atrium of a Roman house, being covered with a shed roof round all four sides and open in the centre, and so resembling a cloister. The side next the church was called the narthex or porch; and when an atrium did not exist, a narthex at least was usually [!-- original location of Fig. 156 --] provided. The basilica has always a central avenue, or nave, and sides or aisles, and was generally entered from the narthex by three doors, one to each division. The nave of San Clemente is lofty, and covered by a simple wooden roof; it is separated from the side aisles by arcades, the arches of which spring from the capitals of columns; and high up in its side walls we find windows. The side aisles, like the nave, have wooden roofs. The nave terminates in a semicircular recess called “the apse,” the floor of which is higher than that of the general structure, and is approached by steps. A large arch divides this apse from the nave. A portion of the nave floor is occupied by an enclosed space for the choir, surrounded by marble screens, and having a pulpit on either side of it. These pulpits are termed “ambos.” Below the Church of San Clemente is a vaulted structure or crypt extending under the greater part, but not the whole, of the floor of the main building.
The description given above would apply, with very slight variations, to any one of the many ancient basilica churches in Rome, Milan, Ravenna, and the other older cities of Italy; the principal variations being that in many instances, including the very ancient basilica of St. Peter, now destroyed, the avenues all stopped short of the end wall of the basilica, and a wide and clear transverse space or transept ran athwart them in front of the apse. San Clemente indeed shows some faint traces of such a feature. In one or two very large churches five avenues occur,—that is to say, a nave and double aisles; and in Santa Agnese (Fig. [156a]) and at least one other, we find a gallery over the side aisles opening into the nave, or, as Mr. Fergusson puts it, “the side aisles in two stories.” In many instances we should find no atrium, [!-- original location of Fig. 156a --] but in all cases we meet with the nave and aisles, and the apse at the end of the nave, with its arch and its elevated floor; and the entrances are always at the end of the building farthest from the apse, with some sort of porch or portal.
Fig. 156a.—Basilica, or Early Christian Church of Santa Agnese at Rome.
The interest of these buildings lies not so much in their venerable antiquity as in the fact that the arrangements of all Christian churches in Western Europe down to the Reformation, and of very many since, are directly derived from these originals. If the reader will refer to the description of a Gothic cathedral in the companion volume of this series,[28] it will not be difficult for him to trace the correspondence between its plan and its general structure and those of the primitive basilica. The atrium no longer forms the access to a cathedral, but it still survives in the cloister, though in a changed position. The narthex or porch is still more or less traceable in the great western portals, and in a kind of separation which often, but not always, exists between the westernmost bay of a cathedral and the rest of the structure. The division into nave and aisles remains, and in very large churches and cathedrals there are double aisles, as there were in the largest basilicas. The nave roof is still higher than the aisles—the arcade, in two stories, survives in the usual arcade and triforium; the windows placed high in the nave are the present clerestory. The apsidal termination of the central avenue is still retained in almost all Continental architecture, though in Great Britain, from an early date, it was abandoned for a square east end; but square-ended or apsidal, a recess with a raised floor and a conspicuous arch, marking it off from the nave, always occupies this end of the church; and the under church, or crypt, is commonly, though not always, met with. The enclosure for the choir has, generally speaking, been moved farther east than it was in the basilica churches; though in Westminster Abbey, and in most Spanish cathedrals, we have examples of its occupying a position closely analogous to that of the corresponding enclosure at the basilica of San Clemente. The cross passage to which we have referred as having existed in the old basilica of St. Peter, and many others, is the original of the transept which in later churches has been made more conspicuous than it was in the basilica by being lengthened so as to project beyond the side walls of the church, and by being moved more westward. Lastly, the two ambos, or pulpits, survive in two senses. They are represented by the reading desk and the pulpit, and their situation and purpose are continued in the epistle and gospel sides of the choir.