It appeared for the first time in history in 338 BC when, after the Latin Wars, it received the Roman status of Civitas sine suffragio as it remained neutral, together with the city of Fondi.

[6] It became a renowned resort during the Republican era for rich Romans to build elaborate villas and Horace called it "the city of the Mamurrae"[7] as the rich and noble equestrian family of Mamurra had strong interests there, including the villa-estate nearby at Gianola, which can still be seen.

The impressive remains of Roman villas still stretch along the coast from the fishponds in the Nuovo Porto to Gaeta.

Many marble sculptures have been removed from these villas, the majority of which are in the Museo Nazionale in Naples, notably a fine pair of Nereids riding on sea monsters.

[13] Sextus Julius Frontinus (40 – 104 AD), “Curator Aquarum” of all the aqueducts of Rome, had a villa in Formiae in which Aelianus met the emperor Nerva.

[15] After the fall of the Western Roman Empire the city was sacked by "barbarians" and the population moved to two distinct burghs on the nearby hill, which were under the rule of Gaeta.

Charles II of Anjou built a fortress in the maritime burgh, Mola di Gaeta.

[16] Formia lies on the Tyrrhenian Sea, in southern Lazio, close to the town of Gaeta and next to the borders of Campania region.