[2][3] The town on the eastern side of Monte Circeo was probably founded by Greeks at the end of the Bronze Age, when they established ports and emporiums along the Italian coast.
Many walls of this type were built during the Bronze Age in the Mediterranean, for example in Lazio those of Segni, Ferentino, Norba and Arpinum, possibly by the Aurunci people of the area.
But in 209 BC, during the Second Punic War, Circeii was one of twelve colonies to refuse any more military contributions towards Rome[12] and in 204 it was punished as a result,[13] by supplying double the greatest number of foot soldiers they had ever provided and 120 horsemen, all chosen from the wealthiest citizens, and to be sent out of Italy.
[17][18][19] At the end of the republic or at latest at the beginning of the imperial period, the city of Circeii was connected to a harbour on the west side of the promontory on the shore of the Lago di Paola (a lagoon, now a considerable fishery) separated from the sea by a line of sand-dunes and connected with it by a Roman channel: Strabo speaks of the city as a small harbour 1.5 kilometres (0.93 mi) north of the west end of the promontory.
[citation needed] North of the city on the Lago di Paola near Sabaudia emperor Domitian built a sumptuous villa[20] extending over a vast area.
Another inscription in the rock near San Felice speaks about this part of the Latin: promonturium Veneris ("promontory of Venus"; the only case of the use of this name) as belonging to the city of Circeii.
Known as the villa dei Quattro Venti, the remains of this large building in the historic centre of San Felice lie along the road that leads to the port.
It is now thought more likely to be a sanctuary according to recent studies by Sapienza University (with the support of the Circeo National Park and the Superintendency of Archaeological Heritage of Lazio) after discovery of a votive inscription, a dedication addressed to a divinity.
The model for the scenographic arrangement on sloping terraces may refer to the great sanctuaries of the city of Pergamum where the temples stand on high podiums and lack a colonnade at the back.
The section near the mouth of Rio Torto was described by Giuseppe Lugli in the 1920s as: "The width of the navigable body of water must have been about 18 m and depth of 4 m; on the sides there were docks for passing of ships and on the banks ran two parallel roads for towing by animals...".
The Fossa Augusta begins near the area called Casarini, just south of the mediaeval convent and inside the Selva Piana a shallow ditch is clearly visible.
Archaeological finds show that the port-canal was originally built in the Sullan period of about 91-88 BC by Lucius Faberius Murena, magistrate of Circei, to whom an inscription is dedicated.
The spring, formerly known as Bagnara, is now given the name of the rich patrician Lucullus who had many elaborate villas and, in 78 BC, entrusted Gnaeus Domitius Amandus (according to a brick stamp) with the task of collecting the waters of that area.
According to legend the delightful villa on the shores of Lake Paola belonged to Lucullus, who after having exercised his military career for many years fighting valiantly and with honour, and after having accumulated much wealth, retired from public office to end his last days in the comfort on the Circeo promontory.
The first phase of the pool was between the end of the republic and the early empire, the same period in which the nearby thermal baths of Torre Paola were built which perhaps shared the supply.