great deal of conjecture has been expended on the question as to the genesis of
the Roman basilica. For present purposes it may be sufficient to observe that
the addition of aisles to the nave was so manifest a convenience that it might
not improbably have been thought of, even had models not been at hand in the
civic buildings of the Empire. The most suitable example that can be chosen as
typical of the Roman basilica of the age of Constantine is the church of S.

Maria Maggiore. And this, not merely because, in spite of certain modern
alterations, it has kept in the main its original features, but also because it
departs, to a lesser extent than any other extant example, from the classical
ideal. The lateral colonnade is immediately surmounted by a horizontal
entablature, with architrave, frieze, and cornice all complete. The monolithic
columns, with their capitals, are, moreover, homogenous, and have been cut for
their position, instead of being like those of so many early Christian churches,
the more or less incongruous and heterogeneous spoils of older and non-Christian
edifices. Of this church, in its original form, no one however decidedly his
tastes may incline to some more highly developed system or style of architecture
will call in question the stately and majestic beauty. The general effect is
that of a vast perspective of lines of noble columns, carrying the eye forward
to the altar, which, with its civory or canopy, forms so conspicuous an object,
standing, framed, as it mere, within the arch of the terminal apse, which forms
its immediate and appropriate background. S. Maria Maggiore is considerably
smaller than were any of the other three chief basilicas of Rome (St Peter's,

St. Paul's, and the Lateran). Each of these, in addition to a nave of greater
length and breadth, was furnished (as may still be seen in the restored St

Paul's) with a double aisle. This, however, was an advantage which was not
unattended with a serious drawback from a purely esthetic point of view. For a
great space of blank wall intervening between the top of the lateral colonnade
and the clerestory windows was of necessity required in order to give support to
the penthouse roof of the double aisle. And it is curious, to say the least,
that it should not have occurred to the builders of those three basilicas to
utilize a portion of the space thus enclosed, and at the same time to lighten
the burden of the wall above the colonnade, by constructing a gallery above the
inner aisle. It is true, of course, that such a gallery is found in the church
of S. Agnese, where the low-level of the floor relatively to the surface of the
ground outside may have suggested this method of construction; but whereas, in
the East, the provision of a gallery (used as a gynaeceum) was usual from very
early times, it never became otherwise than exceptional in the West. Taking East
and West together, we find among early and medieval basilican churches examples
of all the combinations that are possible in the arrangement of aisles and
galleries. They are the single aisle without gallery, which is, of course, the
commonest type of all; the double aisle without gallery, as in the three great

Roman basilicas; the single aisle with gallery, as in S. Agnese; the double
aisle with single gallery, as in St. Demetrius at Thessalonica; and finally, as
a crowning example, though of a later period, the double aisle surmounted by a
double gallery, as in the Duomo at Pisa. These, however, are modifications in
the general design of the building. Others, not less important, though they are
less obviously striking, concern the details of the construction. Of these the
first was the substitution of the arch for the horizontal entablature, and the
second that of the pillar of masonry for the monolithic column. The former
change, which had already come into operation in the first basilica of St. Paul
without the Walls, was so obviously in the nature of an improvement in point of
stability that it is no matter for surprise that it should have been almost.
universally adopted. Colonnaded and arcaded basilicas, as we may call them, for
the most part older than the eleventh century, are to be found in the most
widely distant regions, from Syria to Spain, and from Sicily to Saxony; and the
lack of examples in Southern France is probably due to the destructive invasion
of the Saracens and Northmen and to the building of new churches of