Since Palladio’s time, if not from a much earlier date, the Pons Fabricius has been known as the Ponte Quattro Capi, because its entrance from the left bank has a protective emblem, a quadrupled head of Janus, the guardian deity of gates, and a divinity with many other occupations, all very alert and troublesome. So we must add this pagan emblem to the other symbols of religious faith with which bridges have been sanctified. In 1680 the Pons Fabricius was repaired by Pope Innocent XI. There are two arches, each with a span of 25, 34 metres; and there used to be two other arches, only 3, 50 metres wide, pierced through the abutments, but they have disappeared among the houses on each bankside. The bridge in its greatest width measures a little more than 15 metres. It has a bold cornice ornamented with mutules, and its relief bay for spate water is flanked by pilasters. M. Degrand says of the Pons Fabricius: “C’est le premier pont dans lequel les têtes des voûtes ne forment pas des demi-circonférences: l’intrados est un arc de cercle de 25 m. de rayon et de 20 m. de flèche.” Here we find a starting-point for the lovely arch invented at Avignon by Saint Bénézet ([p. 81]).
3. The Pons Cestius, on the other side of the island, known to-day, and in Palladio’s time, as Ponte S. Bartolommeo. Yet its inscription, which is mentioned by Canina and by Sir William Smith, speaks of it as Pons Gratianus, and commemorates its repair by Valentinian, Valens, and Gratian. It has but one arch, nearly a metre less in span than those of the Pons Fabricius. These two bridges, according to Piranesi, were founded in a very remarkable manner, on reversed arches built under water. Gauthey gives two drawings of this construction, but he does not guarantee the truth of Piranesi’s details.
Five other antique bridges crossed the Tiber at or near Rome, but Palladio found nothing more of them than a few remnants. Already I have spoken of two, the Pons Sublicius and its understudy ([p. 140]). On the left bank, facing the church of S. Spirito, Palladio saw remains of the Pons Triumphalis; but Piranesi and Bunsen do not agree with Palladio. They place the Pons Triumphalis beyond the Pons Ælius, and Sir William Smith thinks it probable that the remains near S. Spirito belong to a bridge which the Mirabilia names Pons Neronianus, and which ancient topographers describe as Pons Vaticanus. Then there was the Janiculine bridge upon the foundations of which, between 1471 and 1484, Pope Sixtus IV had erected the Ponte Sisto. As the Janiculine bridge went from the Janiculum to the Porta Aurelia, it was known also as Pons Aurelius; and in the Middle Ages it seems to have been called Pons Antoninus. As for the Ponte Molle, anciently the Pons Milvius, it belonged to the Flaminian Way, crossing the Tiber beyond the walls of Rome, a mile and a half outside the city. Its founder was said to be the earlier Æmilius Scaurus, who died about eighty-five years before the Birth of Christ. Yet it certainly existed in B.C. 207, for Livy relates how the people poured out of Rome as far as the Milvian bridge in order to meet the messengers who brought tidings of the defeat of Hasdrubal. This may have been a timber bridge, and Æmilius Scaurus may have displaced it for a stone bridge during his consulship, B.C. 110.
Only a few fragments of the Pons Milvius existed in Palladio’s time; and so the Ponte Molle now extant has a false reputation of being Roman. In fact, it is a very poor structure, badly designed and very uncouth.
IV
There was in Italy a Roman bridge built of white Istrian stone that Palladio admired much more than any other; indeed, he admired it too much, for he copied it in most of his pontine architecture, as if he had no right to make use of his own originality! And since his time many architects have cribbed from the same shining model, the Ponte Augustus over the Ariminus, at Rimini. Two Roman bridges are found in the neighbourhood of this town, one with seven arches and one with five; both date from the same great era, and in both the roadway is not carried through on the same level, but has an ascent at each end, like the two bridges of Roman origin at Vicenza. It was the bridge with five arches that Palladio preferred at Rimini, and his fondness for it—or, rather, for her, as this Roman bridge has a charm somewhat feminine—is approved by recent experts, and notably by R. Phené Spiers and M. Degrand. She is a bijou among bridges, and not a male prodigy, like the Puente Trajan. Her arches are small in span, ranging from 8m.77 to 7m.14, according to Gauthey, [79] the narrower ones being at the sides, and the three larger bays in the middle. Their form is semicircular, and their springing does not rise from low water-level, like that of the arches in the Roman bridge at Mérida; it is placed four or five metres[80] above low water, and this planning adds lightness and grace to a fortunate design. As usual, the piers are too heavy, their thickness being about equal to a half of the adjacent voids; they are protected by very vigorous cutwaters that break the current with angular wedges of ninety degrees. The spandrils are decorated with niches, and every niche is flanked by pilasters carrying entablature and pediment. A beautiful cornice supported by modillions crowns this bridge, which was begun by Augustus and finished by Tiberius.
PONTE MAGGIORE OVER A RAVINE OF THE TRONTO AT ASCOLI-PICENO IN ITALY; BUILT IN THE MIDDLE AGES, BUT ROMAN IN STYLE
Brangwyn is fascinated by the bridges at Ascoli-Piceno, the Asculum Picenum of the Romans, that gleams on a terrace dominating the Tronto, about twenty miles from Porto Ascoli on the Adriatic. The town is defended by ravines, across which four great bridges are thrown. The Ponte di Porta Cappucina is a Roman bridge, a fine example with a single arch of 71 ft. span; and the Ponte de Cecco is Roman. It has two arches and belongs to the Via Salaria. As for the Ponte Maggiore and the Ponte Cartaro, they are mediæval, but the former is an adaptation from Roman aqueducts, and in the latter there appear to be some traces of antique craftsmanship. All these great viaducts are marvellously constructed, for they resisted the earthquake that shook Ascoli in 1878.