Nettuno is located on the coast and is practically joined to the beach town of Anzio. On this stretch was Antium, Volscian capital that became a Roman colony in 338 BC. After the Roman Empire and the Barbarian invasions, the rich Roman Anzio disappeared, and the nucleus of a new city formed around the temple of the god Neptune.
In the Middle Ages Nettuno passed from hand to hand among the largest landowners of Latium: the Counts of Tusculum, the monks of Grottaferrata, the Orsini and the Frangipane. The Astura Torre military fortification was built in 1193 based on a drawing by Mariano di Giacomo, called “The Jackdaw”.
Nettuno then passed to the Colonna, the Borgias, the Carafa, back to the Colonna. The latter held it until 1564, when it was passed to the Apostolic Chamber. In 1503 the Sangallo fortress, built by Pope Alexander VI Borgia, designed by Giuliano da Sangallo, was inaugurated. The fort is one of the most significant military works of the Lazio coast.
Nettuno was the favorite place of residence of the members of the Roman Curia that built sumptuous villas.
The Apostolic Chamber in the first half of 1800s yielded to Borghese the territory of Nettuno.
In 1888 the Centre for Artillery Testing was inaugurated for experimentation and testing of weapons and ammunition that was developed along the coast south of Nettuno.
In 1904 Luigi Pirandello set his novel “Va Bene” In Nettuno
On 2 March 1925, in the Forte Sangallo, Benito Mussolini signed the Treaty between Italy and Yugoslavia to adjust the conditions for the Italians in Dalmatia.
January 22, 1944, on the beaches of Nettuno General John Porter Lucas, head of the VI Corps. landed. At the end of the war, the United States of America built a monumental cemetery.