m cruciforme_. A
soldier, dressed in a tunic and mantle, seizes the prisoner with the
right hand, and stabs him in the neck with the left. The weapon used
is not a lictor's axe, nor the sword of a legionary, but a sort of
cutlass, which would be more likely to cut the throat than to sever
the head from the body. The cross is crowned by a triumphal wreath, as
a symbol of the immortal recompense which awaits the confessor of the
Faith. The historical value of this rare sculpture is determined by
the name, ACILLEVS, engraved above it.

[Illustration: The Execution of Acilleus.]

The character of the letters and the style of the bas-relief are those
of the second half of the fourth century. Of the sister column, with
the name and martyrdom of NEREVS, only a small bit has been found.
Another monument of equal value is a broken slab containing, in the
first line, the letters ....RVM; in the second, the letters ....ORVM;
and below these, the cross-shaped anchor, the mysterious but certain
emblem of Christian hope. As the position of the symbol determines the
middle point of the inscription, it is easy to reconstruct the whole
text, by a careful calculation of the size of each letter:--

[Illustration: SEPVLCRVM FLAVIORVM]

"the tomb of the Flavian family," namely, of those relatives of
Domitilla who had embraced the Christian faith.

Under the pavement of the nave, aisles, and presbytery, are numberless
graves, some of which belong to the original catacombs, before they
were cut and disarranged by the building of the basilica; others are
built in accordance with the architectural lines of the basilica
itself. A grave belonging to the first series, that is, to a gallery
of the catacombs which had been blocked by the foundations of the left
aisle, bears the date of the year 390; while a sarcophagus placed at
the foot of the altar is dated Monday, May 12, 395. It is evident,
therefore, that the basilica was built between 390 and 395, during the
pontificate of Siricius.

No memorial of Petronilla, the third saint for whom the building was
named, has been found within the sacred enclosure,--a fact not wholly
unexpected, because the coffin in which her remains were placed is
known to have been removed to the Vatican by Paul I. (755-756), at the
request of the king of France. In November, 1875, a cubiculum was
found at the back of the apse, connected with it by a corridor which
opens near the episcopal chair. The walls of this