The Porta San Sebastiano has two fine semicircular towers of the Aurelian wall, resting on a basement of marble blocks, probably plundered from the tombs on the Via Appia. Under the arch is a gothic inscription relating to the repulse of some unknown invaders.

It was here that the senate and people of Rome received in state the last triumphant procession which has entered the city by the Via Appia, that of Marc-Antonio Colonna, after the victory of Lepanto in 1571. As in the processions of the old Roman generals, the children of the conquered prince were forced to adorn the triumph of the victor, who rode into Rome attended by all the Roman nobles, "in abito di grande formalità,"[197] preceded by the standard of the fleet.

From the gate, the Clivus Martis (crossed by the railway to Civita Vecchia) descends into the valley of the Almo, where antiquaries formerly placed the Porta Capena. On the hillside stood a Temple of Mars, vowed in the Gallic war, and dedicated by T. Quinctius the "duumvir sacris faciundis," in B.C. 387. No remains exist of this temple. It was "approached from the Via Capena by a portico, which must have rivalled in length the celebrated portico at Bologna extending to the church of the Madonna di S. Luca."[198] Near this, a temple was erected to Tempestas in B.C. 260, by L. Cornelius Scipio, to commemorate the narrow escape of his fleet from shipwreck off the coast of Sardinia.[199] Near this, also, the poet Terence owned a small estate of twenty acres, presented to him by his friend Scipio Emilianus.[200] After crossing the brook, we pass between two conspicuous tombs. That on the left is the Tomb of Geta, son of Septimius Severus, the murdered brother of Caracalla; that on the right is the Tomb of Priscilla, wife of Abascantius, a favourite freedman of Domitian.

"Est locus, ante urbem, qua primum nascitur ingens
Appia, quaque Italo gemitus Almone Cybele
Ponit, et Idæos jam non reminiscitur amnes.
Hic te Sidonio velatam molliter ostro
Eximius conjux (nec enim fumantia busta
Clamoremque rogi potuit perferre), beato
Composuit, Priscilla, toro."
Statius, lib. v. Sylv. i. 222.

Just beyond this, the Via Ardeatina branches off on the right, passing, after about two miles, the picturesque Vigna Marancia, a pleasant spot, with fine old pines and cypresses.

Where the roads divide, is the Church of Domine Quo Vadis, containing a copy of the celebrated footprint said to have been left here by Our Saviour: the original being removed to S. Sebastiano.

"After the burning of Rome, Nero threw upon the Christians the accusation of having fired the city. This was the origin of the first persecution, in which many perished by terrible and hitherto unheard-of deaths. The Christian converts besought Peter not to expose his life. As he fled along the Appian Way, about two miles from the gates, he was met by a vision of our Saviour travelling towards the city. Struck with amazement, he exclaimed, 'Lord, whither goest thou?' to which the Saviour, looking upon him with a mild sadness, replied, 'I go to Rome to be crucified a second time,' and vanished. Peter, taking this as a sign that he was to submit himself to the sufferings prepared for him, immediately turned back to the city.[201] Michael Angelo's famous statue, now in the Church of Sta. Maria sopra Minerva, is supposed to represent Christ as he appeared to St. Peter on this occasion. A cast or copy of it is in the little church of 'Domine, quo vadis?'

"It is surprising that this most beautiful, picturesque, and, to my fancy, sublime legend, has been so seldom treated; and never, as it seems to me, in a manner worthy of its capabilities and high significance. It is seldom that a story can be told by two figures, and these two figures placed in such grand and dramatic contrast;—Christ in His serene majesty, and radiant with all the joy of beatitude, yet with an expression of gentle reproach; the Apostle at his feet arrested in his flight, amazed, and yet filled with a trembling joy; and for the background the wide Campagna, or towering walls of imperial Rome."—Mrs. Jameson.[202]

Beyond the church is a second "Bivium," or cross-ways, where a lane on the left leads up the Valle Caffarelle. Here, feeling an uncertainty which was the crossing where Our Saviour appeared to St. Peter, the English Cardinal Pole erected a second tiny chapel of "Domine Quo Vadis," which remains to this day.

On the left, is the Columbarium of the Freedmen of Augustus and Livia, divided into three chambers, but despoiled of its adornments. Other Columbaria near this are assigned to the Volusii, and the Cæcilii.