Why the year 320? The city may have been at a population peak, but all of its major architecture was already 200 years old, except for Caracella’s Baths, which were 100 years old. Of course within a few years, as first Constantinople was established, and then the western capital moved to northern Italy, Rome went into a rapid decline, which was accelerated by the sacking of the city first by the Visigoths, then by the Vandals.
Hope Hussein doesn’t get any ideas with Washington...
Yes. I'd rather look at 320 BC, or the port of Cosa around 100 BC. Better still I'd like to dig up even a partial Etruscan-Latin dictionary!