_Archaeologia,_ vol. liii.)]

An early Christian basilica may be thus described in its main features:--A
porch supported on pillars (as at S. Clemente) gave admission into an open
court or _atrium_, surrounded by a colonnaded cloister (S. Clemente, Old St
Peter's, S. Ambrogio at Milan, Parenzo). In the centre of the court stood a
cistern or fountain (_cantharus_, _phiale_), for drinking and ablutions. In
close contiguity to the atrium, often to the west, was the baptistery,
usually octagonal (Parenzo). The church was entered through a long narrow
porch (_narthex_), beyond which penitents, or those under ecclesiastical
censure, were forbidden to pass. Three or more lofty doorways, according to
the number of the aisles, set in marble cases, gave admission to the
church. The doors themselves were of rich wood, elaborately carved with
scriptural subjects (S. Sabina on the Aventine), or of bronze similarly
adorned and often gilt. Magnificent curtains, frequently embroidered with
sacred figures or scenes, closed the entrance, keeping out the heat of
summer and the cold of winter.

The interior consisted of a long and wide nave, sometimes as much as 80 ft.
across, terminating in a semicircular apse, with one or sometimes (St
Paul's, Old St Peter's, St John Lateran) two aisles on each side, separated
by colonnades of marble pillars supporting horizontal entablatures (Old St
Peter's, S. Maria Maggiore, S. Lorenzo) or arches (St Paul's, S. Agnese, S.
Clemente, the two basilicas of S. Apollinare at Ravenna). Above the pillars
the clerestory wall rose to a great height, pierced in its upper part by a
range of plain round-headed windows. The space between the windows and the
colonnade (the later triforium-space) was usually decorated with a series
of mosaic pictures in panels. The colonnades sometimes extended quite to
the end of the church (the Ravenna basilicas), sometimes ceased some little
distance from the end, thus admitting the formation of a transverse aisle
or transept (St Paul's, Old St Peter's, St John Lateran). Where this
transept occurred it was divided from the nave by a wide arch, the face and
soffit of which were richly decorated with mosaics. Over the crown of the
arch we often find a bust of Christ or the holy lamb lying upon the altar,
and, on either side, the evangelistic symbols, the seven candlesticks and
the twenty-four elders. Another arch spanned the semicircular apse, in
which the church always terminated.