There is abundant evidence as to the position of this bridge, for the Fasti Capranici place it ad Theatrum Marcelli, and the Cosmographia of Æthicus ad Forum Boarium, both of which indications point to the Ponte Rotto.
Island of the Tiber.
A short distance above the Æmilian bridge is the island of the Tiber. According to the legend, this island was formed by the corn belonging to the Tarquins grown on the Campus Martius, which after their expulsion was consecrated to Mars. After consecration the corn could not be used for food, and was therefore cut and thrown into the Tiber, and from this corn, when collected into heaps by the stream, the island was formed. Until the fifth century of the city, the island remained consecrated and uninhabited, but in B.C. 292 a Temple of Æsculapius was built upon it in consequence, as the story went, of the holy snake brought from Epidaurus having swum to shore there. The island was probably at this time also protected with stone embankments, and the two bridges were built, whence the name inter duos pontes was given to it. A fragment of this ancient stone embankment, which was in the shape of a ship, may still be seen in the garden of the Franciscan Monks of S. Bartolommeo, representing part of the prow of a ship, with a snake and the head of an ox carved in relief upon it.
The two bridges uniting the island to either bank were probably, as has been said, first erected in or about the fifth century of the city, but the existing bridges, though ancient, must be considered as restorations of the older fabrics.
The bridge on the side towards the Campus Martius was built by L. Fabricius in B.C. 62, as the inscription still extant on the bridge shows. In accordance with this we find Dion Cassius giving it the name of Pons Fabricius, and a coin with the title L. Fabricius gives on the other side a bridge with a snake, plainly pointing to the island of the Tiber.
Another inscription, also still remaining upon the bridge, states that it was examined and found in good repair by Q. Lepidus and M. Lollius, consuls in B.C. 21.
This bridge is the oldest now standing on the Tiber, and the masonry is of admirable solidity and workmanship. It was called, in the Middle Ages Pons Judæus, from its proximity to the Jews’ quarter of the city, and now bears the name Quattro Capi from the jani quadrifrontes which stand upon it.[84] These jani were formerly the posts which supported the railings of the bridge, as may be seen by the holes bored in them for the ancient bronze bars.
The twin bridge on the right-hand side of the river, dates from the imperial era, and probably, like the Pons Fabricius, replaced a much older bridge of the same age as the Temple of Æsculapius.
Two inscriptions are still legible on this bridge, from which we learn that it was finished in the year A.D. 370, and dedicated to the use of the Roman people in the name of the Emperor Gratianus, by Valentinian, Valens and Gratianus. These inscriptions must be understood as referring to the rebuilding of the bridge, though they are so worded as to claim the credit of its first erection. That there was an older bridge is clear, not only from the fact that the island was called inter duos pontes before the time of Gratian, but also from the name pons Cestius, which occurs in the Notitia, and undoubtedly belongs to that bridge. It is not clear who Cestius was, but it is generally supposed that a præfectus urbi of that name in B.C. 46 is the person after whom the bridge was named, and this agrees with the statement of Dion Cassius about the building of the Fabrician bridge.
The church of S. Nicola in Carcere, which stands in the Via della Bocca della Verità close to the Piazza Montanara, contains the remains of two or perhaps of three temples.