BASILICA CONSTANTINI

77

long, 25 wide and 35 high, with side aisles 16 metres wide and 24.50 high.
These aisles were divided into three sections by walls pierced by wide
arches and ending on each side of the nave in massive piers. In front of
these piers and at the corners of the nave were eight monolithic columns
of marble, all of which have been destroyed except one that was removed
by Paul V in 1613 to the Piazza di S. Maria Maggiore, where it now stands
(LS ii. 209 ; JRS 1919, 180). The height of the shaft of this column
is 14.50 metres, and it is 5.40 metres in circumference. On the piers
rested the roof of the nave, divided into three bays with quadripartite
groining. The ceiling was decorated with deep hexagonal and octagonal
coffers. For the entasis see Mem. Am. Acad. iv. 122, 142.
The facade of the basilica as built by Maxentius was towards the east,
and at this end was a corridor or vestibule, 8 metres deep, which extended
across the whole width of the building. From this vestibule there were
five entrances into the basilica, three into the nave, and one into each of the
aisles. A flight of steps led up from the street in front to the vestibule,
which was adorned with columns. At the west end of the nave was a
semicircular apse, 20 metres in diameter, in which the fragments of the
colossal statue of Constantine, now in the Palazzo dei Conservator!, were
probably found in 1487 (HC 242 ; Cons. 5, 11 fl.). The statue probably
sat in this apse, which would have been its natural place.
Constantine spoilt the original conception of the building when he
constructed a second entrance from the Sacra via in the middle of the
south side, where he built a porch with porphyry columns (?) and a long
flight of steps (III. IO). Opposite this new entrance he constructed a
second semicircular apse in the north wall, as large as that at the west end
of the nave but lower (PBS ii. pls. 16, 59 ; CR 1905, 76). Thenceforth
the basilica produced the same impression—of three parallel halls—
whether one entered it from the south or from the east.
Besides the foundation, which has been almost wholly uncovered,
the north wall and the north aisle—or, as it rather appears, the north
sections of the three halls regarded as running north and south—are
still standing. The semicircular apse in the central hall contains sixteen
rectangular niches in two rows, with a pedestal or suggestus in the
centre. A marble seat with steps runs round the apse, which was
separated from the rest of the hall by two columns and marble screens,
thus forming a sort of tribunal. Nothing of the nave remains except
the bases of the great piers. The core of the porch and of the flight of
steps leading down to the Sacra via is still visible, and several fragments
of the porphyry columns have been set up, but not in situ. Of the
pavement of slabs of marble considerable fragments have been found
(Mitt. 1905, 117).
The material employed in this basilica was brick-faced concrete
(AJA 1912, 429-432), and the great thickness of the walls—6 metres at
one point at the west end—and the enormous height and span of the