laid together, then a range for older children, and then one for the
grown up. Sometimes, instead of a grave suitable for a single body, the
excavation is made deep enough into the rock to admit of two, three, or
four bodies being placed side by side,--family graves. And sometimes,
instead of the simple _loculus_, or coffin-like excavation, there is
an arch cut out of the tufa, and sunk back over the whole depth of the
grave, the outer side of which is not cut away, so that, instead of
being closed in front by a perpendicular slab of marble or by tiles, it
is covered on the top by a horizontal slab. Such a grave is called an
_arcosolium_, and its somewhat elaborate construction leads to the
conclusion that it was rarely used in the earliest period of the
catacombs[E]. The _arcosolia_ are usually wide enough for more than
one body; and it would seem, from inscriptions that have been found upon
their covering-slabs, that they were not infrequently prepared during
the lifetime of persons who had paid beforehand for their graves. It is
not improbable that the expenses of some one or more of the cemeteries
may have been borne by the richer members of the Christian community,
for the sake of their poorer brothers in the faith. The example of
Nicodemus was one that would be readily followed.

[Footnote E: There is one puzzling circumstance in the cemetery of S.
Domitilla. _All_ the graves in this cemetery are _arcosolia_, and yet
the date of construction is early. The Cavaliere de Rossi suggests that
the cemetery was begun at the expense of the Domitilla whose name it
bears, the niece of Domitian, previously to her banishment; that her
position enabled her to have it laid out from the beginning on a regular
plan, and to introduce this more expensive and elaborate form of
grave, which was continued for the sake of uniformity in the later
excavations.]

But beside the different forms of the graves, by which their general
character was varied, there were often personal marks of affection
and remembrance affixed to the narrow excavations, which give to the
catacombs their most peculiar and touching interest. The marble facing
of the tomb is engraved with a simple name or date; or where tiles take
the place of marble, the few words needed are scratched upon their hard
surface. It is not too much to say that we know more of the common faith
and feeling, of the sufferings and rejoicings of the Christians of the
first two centuries