Following the narrow lane behind S. Pietro, we reach, on the left, S. Martino al Monte, the great church of the Carmelites, which, though of uninviting exterior, is of the highest interest. It was built in A.D. 500 by S. Symmachus, and dedicated to the saints Sylvestro and Martino, on the site of an older church founded by St. Sylvester in the time of Constantine. After repeated alterations, it was modernised in 1650 by P. Filippini, General of the Carmelites. The nave is separated from the aisles by twenty-four ancient Corinthian columns. The aisles are painted with landscapes by Gaspar Poussin, having figures introduced by his brother Nicholas. The roof is an addition by S. Carlo Borromeo.
The pillars of different marbles are magnificent, and the effect of the raised choir, with winding staircases to the crypt below, is highly picturesque. On the walls are frescoes by Cavaluccio (ob. 1795), who is buried in the left aisle. The collection of incised gravestones deserves attention, they comprise those of a knight in mail armour of 1349; Cardinal Diomede Caraffa, with a curious epitaph; and various generals and remarkable monks of the Carmelite Order. Beneath the high altar rest the bodies of Popes Sergius, Sylvester, Martin I., Fabian, Stephen I., Soter, Ciriacus, Anastasius, and Innocent I., with several saints not papal, removed hither from the catacombs. In the curious crypt, part of the Baths of Titus, the early Council of Sylvester and Constantine was held, as represented in the fresco in the left aisle of the upper church. The back of the ancient chair of Sylvester still remains, green with age and damp. In the chapel on the left, where St. Sylvester used to celebrate mass, is an ancient mosaic of the Madonna. In front of the papal chair is the grand sepulchral figure of a Carmelite, who was General of the Order in the time of Sta. Teresa. An urn contains the intestines of the "Beato," Cardinal Giuseppe-Maria de Tommasis, who died in 1713. His body is preserved beneath an altar in the left aisle of the upper church, and is dressed in his cardinal's robes.
"In 1650 was reopened, beneath SS. Martino e Sylvestro, the long-forgotten oratory formed (according to Anastasius) by Sylvester among the halls of Trajan's Thermæ—or, more probably, in an antique palace adjacent to those imperial baths—and called by Christian writers 'Titulus Equitii,' from the name of a Roman priest then proprietor of the ground. Now a gloomy, time-worn, and sepulchral subterranean, this structure is in form an extensive quadrangle, under a high-hung vault, divided into four aisles by massive square piers; the central bay of one aisle adorned with a large red cross, painted as if studded with gems; and ranged round this, four books, each within a nimbus, earliest symbolism to represent the Evangelists. Among the much-faded and dim-seen frescoes on these dusky walls, are figures of the Saviour between SS. Peter and Paul, besides other saints, each crowned by a large nimbus."—Hemans' Ancient Sacred Art.
Here is preserved a mitre, probably the most ancient extant, and said to be that of St. Sylvester, who lived in the fourth century, and who was the first Latin bishop to wear the mitre originally worn by the priests of pagan temples. This ancient mitre is so low as to rise only just above the crown of the head.
This church was dedicated to St. Martin, the holy Bishop of Tours, within a hundred years after his death, showing the very early veneration with which that saint was regarded.
Leaving S. Martino by the other door, near the tribune, we emerge at the top of the steep street called Sta. Lucia in Selci, which is the same with that described by Martial in going to visit the younger Pliny as—
"Altum vincere tramitem Suburræ." Lib. x. Ep. 19, 5.
And again—
"Alto Suburrani vincenda est semita clivi." Lib. v. Ep. 23, 5.
Here is a whole group of convents. In the hollow is the convent of S. Francesco di Paola, with several others. Just above (in the Via Quattro Cantone) is the convent of the Oratorians, or S. Filippo Neri. At this point also are two mediæval towers, one enclosed within the convent walls of Sta. Lucia in Selci, the other on the opposite side of the street, supposed by some to be the tower of Mecænas, celebrated by Horace. On the left of the street is the house of Domenichino (Domenico Zampieri), whose residence here is commemorated by an inscription.