e reduced to their right measure,
form an immense work."[5] This could only be executed by a large and
powerful Christian community unimpeded by legal enactments or police
regulations, "a living witness of its immense development corresponding
to the importance of the capital." But although, as we have said, in
ordinary times there was no necessity for secrecy, yet when the peace of
the Church was broken by the fierce and often protracted persecutions of
the heathen emperors, it became essential to adopt precautions to
conceal the entrance to the cemeteries, which became the temporary
hiding-places of the Christian fugitives, and to baffle the search of
their pursuers. To these stormy periods we may safely assign the
alterations which may be traced in the staircases, which are sometimes
abruptly cut off, leaving a gap requiring a ladder, and the formation of
secret passages communicating with the _arenariae_, and through them
with the open country.

When the storms of persecution ceased and Christianity had become the
imperial faith, the evil fruits of prosperity were not slow to appear.
Cemetery interment became a regular trade in the hands of the
_fossores_, or grave-diggers, who appear to have established a kind of
property in the catacombs, and whose greed of gain led to that
destruction of the religious paintings with which the walls were
decorated, for the quarrying of fresh _loculi_, to which we have already
alluded. Monumental epitaphs record the purchase of a grave from the
fossores, in many cases during the lifetime of the individual, not
unfrequently stating the price. A very curious fresco, found in the
cemetery of Calixtus, preserved by the engravings of the earlier
investigators (Bottari, tom. ii. p. 126, tav. 99), represents a "fossor"
with his lamp in his hand and his pick over his shoulder, and his tools
lying about him. Above is the inscription, "Diogenes Fossor in Pace
depositus."

Decoration.

It is unnecessary to enter on any detailed description of the frescoes
which cover the walls and ceilings of the burial-chapels in the richest
abundance. It must suffice to say that the earliest examples are only to
be distinguished from the mural decorations employed by their pagan
contemporaries (as seen at Pompeii and elsewhere) by the absence of all
that was immoral or idolatrous, and that it was only very slowly and
timidly that any distinctly religious representations were introduced.
These were a