Alsium

In 247 BC a Roman colonia maritima[7] was established there and which gave them exemption from all military service, which was, however, overruled during the exigencies of the Second Punic War.

[8][9] It is mentioned by Strabo, Pliny, and Ptolemy, and it still retained its colonial rank (from an inscription of the time of Caracalla), and corresponding municipal organisation.

[10][11] It become a favourite resort with wealthy Romans as a place of retirement and pleasure;[12] and Pompey the Great had a villa there, and Julius Caesar also, where he landed on his return from Africa, and at which all the nobles of Rome hastened to greet him.

[13] Another is mentioned as belonging to Lucius Verginius Rufus, the guardian of Pliny, and emperor Marcus Aurelius had a villa there, to which several of his epistles are addressed.

Northeast of Palo is a row of large mounds called I Monteroni, which belong to tombs of the Etruscan cemetery.