It remains to visit Terracina and Circeii, at the southern end of the plain. At Terracina the Via Appia was brought to a halt at the seaboard by a sharp rocky ledge projecting into the sea and forming the last offshoot of the Ausonian range. The Roman engineers at first shirked the difficulty by carrying the road over the hill but later they decided to cut away the face of the rock and have left on its surface their marks and measurements in lengths of one hundred twenty feet which we still can read. The rock called Pisco Montano now rises like a needle.
Terracina is the only one of all the ancient cities we have passed which bridges the chasm between the legendary age and the Empire. On account of its healthy position beyond the marshes, its excellent port and its central location between Rome and Campania, it never lost importance. Augustus rebuilt its forum and Capitoline temple. The temple remains, one of the best preserved examples in Italy of Augustan architecture. The cella wall still keeps in its rear a large part of the rich marble revetment which at just this time was taking the place of the stucco. The Appia, in traversing the city, entered the upper end of the forum through an arch which still remains in part. Even the flags of the area of the forum are in place, with the unique distinction of bearing the signature of the architect, Artorius Primus, evidently the author of the whole scheme, the temple, the memorial arch adjoining it, the square, the Augusteum. Tiberius also liked the city. Trajan, when he repaired the Appian way, began the works on the port that were completed by Antoninus Pius and Marcus Aurelius, and made of it one of the finest on the coast.
Then, if we follow the ancient road out of the town and up along the hillside to the northeast we find it lined at intervals with ancient sepulchral monuments, which give a better impression of such an arrangement than any other road I have seen besides those of Rome and Pompeii, which are, of course, infinitely superior.
The interest and uniqueness of Terracina are increased by the colossal substructures that crown the hill overlooking the city. They consist of lines of high and broad vaulted arcades of excellent brickwork on which some structure of great size and magnificence must once have stood. The vulgar named it Palace of Theodoric, because the Gothic king was known to have liked the city and to have lived here. But the brick-work has recently been found to be of the finest Augustan or even pre-Augustan type and excavations have shown it to be the substructure for a large temple of Jupiter Anxur, the famous youthful, beardless Jupiter, the boy god, son of Saturn. In a way it must have almost rivaled the temple of Fortune at Palestrina, with which it was closely connected. They were respectively the northern and southern outposts and beacon-lights of Latin faith. If one stands on this rocky promontory, jutting into the sea at a height of over a thousand feet, I think the site will give one a strong sense of the hypnotic effect of one of these wonderfully situated ancient shrines, whether on a mountain top or by the sea. Certainly the original shrine was earlier than Augustus and coeval with the city. No substructures of this monumental character exist elsewhere. The gulf of Gaeta on the left, the free sea in front, Circeii and the marshes to the right form the panorama.
Terracina is still a vivid bit of color. The old town away from the hideous modern port, especially around the cathedral square, is often crowded with people of oriental blood or dressed in strong oriental colors, a breath from the Levant. One feels, as at Ravenna, that there was here no great break between ancient and medieval life, and that since the Middle Ages, when Byzantium helped to bridge the chasm, there has happened nothing new. Seen in the rear, from one of the narrow streets filled with antique color, the cella of the Capitol temple has so much of its marble revetment, mellowed by, time, that one expects to see its gable rise in the square, in place of its gorgeous medieval Campanile. But the columns of its porch are those of the temple portico, and on one of them is a most curious link with the past, one of the few public Byzantine inscriptions, stating that the church and square were repaired and cleaned under the Byzantine emperor Constantine in the eighth century. The cathedral itself was rebuilt by those wonderful neo-classic semi-oriental artists of medieval Rome and filled with their furniture and pavements of mosaic inlay.
When we remember the stretch of polygonal wall remaining from the Latin-Volscian city, below the forum, the ancient shrine of Jupiter Anxur, the Augustan forum, the Antonine port and the double line of mausoleums outside the walls, Terracina seems well worth a visit, regardless of its wonderful scenery and picturesqueness and, not the least, of the fact that here one can take boat to Circeii.