Topical Collection - Architecture: Bridges
Research Notes: There is still much debate as to which bridge is depicted on the reverse. The traditional identification has been the Milvian Bridge. Here is an engraving by Giovanni Battista Piranesi, "Ponte Milvio" from the 18th century.
The Milvian Bridge is where Constantine the Great and Maxentius battled in 312. The bridge is part of the Via Flaminia and spans the Tiber River a few miles north of Rome. The bridge may have originally been constructed of wood in 220 BC, but was rebuilt with stone in 109 BC. Perhaps the bridge at one time did look like the one on the coin. The one standing today only contains parts of the ancient bridge.
Take note of the towers on the far end. Those do look similar to the coin, but without the round objects on top, thought possibly to be signal beacons by come numismatists.
Here is a photograph of how the Milvian Bridge stands today.
So, it seems the bridge still looks similar to what Piranesi engraved in the 18th century. The prominence of the arches are not depicted on the coin, but water flowing under the bridge is. Unless the water height was very high, if this were the bridge on the coin, the structure would be very much out of perspective, if the current bridge is anything like the original.