Palo is well known to travellers as the half-way house between Rome and Civita Vecchia ;but few bear in mind hat the post-house, the ruined fortress, and the few fishers' huts on the beach, represent the Alsium of antiquity—one if the most hoary towns of Italy, founded or occupied by he Pelasgi, ages before the arrival of the Etruscans on these shores.

It is strange that no record is preserved of Alsium during the Etruscan period; but this may be owing to its dependence on Cære, with whose history and fortunes its own were probably identical. That it was occupied by the Etruscans we learn from history, confirmed by recent researches. The earliest notice of it by Roman writers is its receiving a colony in the year 507. At no time does it seem to have been of much importance; the highest condition it attained, as far as we can learn, being that of a small town. This may have been owing to its unhealthy position, on a low swampy coast. Yet it was much frequented by the wealthy Romans; and even the Emperor Antoninus chose it as his retreat, and had an Imperial villa on this shore.