nts are occupied by arched sepulchral
recesses, above and below which are tiers of ordinary graves or
_loculi_. The arrangements are certainly such as indicate a
congregational purpose, but the extreme narrowness of the suite, and
still more of the passage which connects the two divisions, must have
rendered it difficult for any but a small number to take any intelligent
part in the services at the same time. Although the idea of the use of
the catacombs for religious worship may have been pressed too far, there
can be no doubt that the sacred rites of the church were celebrated
within them. We have already spoken of the eucharistic celebrations of
which the _cubicula_ were the scene; and still existing baptisteries
prove that the other sacrament was also administered there. The most
remarkable of these baptisteries is that in the catacomb of San
Pontianus (fig. 15). Ten steps lead down to a basin of sufficient depth
for immersion, supplied by a spring. Some of the subterranean chambers
contain armed seats and benches cut out of the tufa rock. These are
supposed by Marchi and others to indicate schoolrooms, where the
catechumens were instructed by the bishop or presbyters. But this theory
wants verification. It is impossible not to be struck with the
remarkable analogy between these rock-hewn chairs and those discovered
in the Etruscan tombs, of the purpose of which no satisfactory
explanation has been given.

[Illustration: FIG. 14.--Bishop's Chair. Catacomb of Sant' Agnese.]

[Illustration: FIG. 15.--Baptistery of San Pontianus. (From Perret.)]

Theories of the use of the catacombs.

Very exaggerated statements have been made as to the employment of the
catacombs as dwelling-places by the Christians in times of persecution.
We have, however, sufficient evidence that they were used as places of
refuge from the fury of the heathen, in which the believers--especially
the bishops and clergy, who would naturally be the first objects of
attack--might secrete themselves until the storm had blown over. This
was a purpose for which they were admirably adapted both by the
intricacy of their labyrinthine passages, in which any one not
possessing the clue would be inevitably lost, and the numerous small
chambers and hiding-places at different levels which might be passed
unperceived in the dark by the pursuers. As a rule also the catacombs
had more than one entrance, and frequently communicated with an
_arenaria_ or sand-