columns of
Tyrian marble, supposed to have been brought to Rome by Titus from the
Temple of Jerusalem. They originally decorated the confessional of the
old Basilica. The twenty-eight steps of the Scala Santa at the
Lateran, said by ecclesiastical tradition to have belonged to Pilate's
house in Jerusalem, and to have been the identical ones which our
Saviour descended when He left the judgment-hall, are made of this
marble; so that, whatever we may think of the tradition itself, there
is a feature of verisimilitude in the material.

The chief supply of pure white marble in Rome was derived from the
quarries in the mountains at Luna, an old Etruscan town near the Bay
of Spezia, which fell to decay under the later Roman emperors. This
ancient _Marmor Lunense_ is called by the Italians Marmo di Carrara,
because it is identical with the famous modern Carrara marble, and
belongs to the same range of strata; the ruins of the ancient Luna
being only a few miles from the flourishing town of Carrara, the
metropolis of the marble trade. From Parian and Pentelic marble, Lunar
marble, as already mentioned, can be easily distinguished by the less
brilliant sparkle of its crystal facets, as shown by a fresh surface,
and also by its more soapy-white colour. It is simply an ordinary
Jurassic limestone altered by subsequent metamorphic action. The
mountains which contain the quarries are highly picturesque, rising
with serried outline to a height of upwards of five thousand feet,
their flanks scarred by deep gorges and torrent-beds, and their lower
slopes clothed with olive groves, vineyards, and forest trees. Lunar
marble was first brought to Rome in the time of Julius Caesar; and
Mamurra, so bitterly reviled by Catullus, the commander of the
artificers in Caesar's army in Gaul, lined with great slabs of this
marble the outside and inside of his house on the Coelian Hill--the
first recorded instance of veneering or incrusting walls with marble.
The discovery of this method of cutting marble into thin slices, and
decorating structures of ordinary materials with them, was stigmatised
by Pliny as an unreasonable mode of extending luxury. The use of Lunar
marble, on account of its easy accessibility, speedily extended to
every kind of building, public and private. So vast were the
quantities sent to Rome, that Ovid expressed his fear lest the
mountains themselves should disappear through the digging out of this
marble; and Pliny anticipat