The usual entrance from the street is by a side door, but the proper
entrance is by a gate with a Gothic canopy of the thirteenth century,
which originally formed part of the earlier basilica, thence through
the atrium and quadriporticus, the only perfect ones of Rome. The
aisles are formed by sixteen ancient pillars of different materials
and orders. In the middle of the nave is the choir (514-22) from the
earlier basilica; on each side are the ambones. The walls are adorned
with Christian emblems, and a monogram of Agios--Holy. The nave is
separated from the high altar by an ancient marble screen. Behind is
the presbytery, which contains an ancient episcopal chair, with the
name of Anastasius, who was titular cardinal of the church in 1108,
engraved upon it. Upon the vault is a mosaic of 1297, representing
Christ on the Cross, from the foot of which issue the four rivers of
Paradise, with shepherds and their flocks, and peacocks. On the face
of the arch is a mosaic of the time of Paschal II.--our Saviour; on
either side two angels, and the emblems of the four evangelists; below
are S. Peter, S. Clement, Jeremiah, S. Paul, S. Lawrence, and Isaiah;
at the bottom, Bethlehem and Jerusalem, with the mystic lamb and
sheep. In the chapel, on the right, the statue of S. John is by
Simone; on the left, the picture of the Virgin is by Conca. The
monument composed of two half-columns, with basket-work capitals and
foliage reliefs, is to Cardinal Venerio, who died in 1479. _To the
left on entering_, in the Chapel of the Passion, are the interesting
frescoes by Masaccio (much spoilt by restoration), representing the
Crucifixion, &c., and events from the lives of SS. Clement and
Catherine. _Outside_ the arch, the Annunciation, and S. Christopher
carrying the infant Christ over a stream; _within_, S. Catherine
forced to Idolatry, Instruction of the King's Daughter in Prison,
Dispute with the Doctors, Miracle of her Deliverance, Martyrdom.
Opposite is the history of S. Clement. _Proceeding into the sacristy_,
which is adorned with paintings of various interesting parts of the
more ancient buildings, _a wide stair conducts to the_