Ponte Cestio, Rome · Wikimedia Commons

Pons Cestius

Cestian Bridge

BridgeItalia · Rome, ItalyBuilt 46 BCE

About

A Roman magistrate named Lucius Cestius built this bridge in the mid-40s BCE to link Tiber Island to the Trastevere bank, completing the island's connection to both shores alongside its older sister crossing, the Pons Fabricius. Legend held that a sacred serpent from Epidaurus had swum ashore on the island during a 3rd-century BCE plague, prompting Rome to build a temple to the healing god Aesculapius there, and this bridge became the main route pilgrims used to reach it. The bridge would eventually need a full imperial restoration under Valentinian, Valens, and Gratian in 370 CE, but through Trajan's reign it still stood on its original Republican-era masonry. Trastevere's residents crossed it daily to reach the heart of the city.

What happened here

Piers are set on cofferdams — a ring of driven piles, pumped dry, filled with concrete that sets under water. They are built with a cutwater pointing upstream to split the current and the ice. The span above may be stone arches or timber on stone, and timber is not a poor relation: it is cheaper, faster, and replaceable. Roads approach on an embankment so the crossing stays level. Tolls are common, shrines at either end are usual, and the inscription names whoever paid. Floods are the enemy; a bridge is inspected after every big one, and the scour around the piers is packed with rubble. A bridge fixes a town's position for a thousand years, which is why so many are still standing.