The hypothesis that the town of Circeii was historically founded under Tarquin the Proud by Arrunte, one of his sons (Liv., I, 56, 3; Dionys., IV, 63 ,1) has been denied for a long time but, in light of the latest findings, it is probably time to re-assess it together with the annalistic tradition.
The turbulent times following the collapse of the hegemony of Rome's last three kings are hard to define. Violent clashes took place to determine who should rule in Latium. Such clashes between Romans and Latins made it possible for Volsci people to get stronger in southern Latium.
Although the annalistic tradition records a series of victories of the Roman-Latin alliance, it is almost sure that the anti-Volsci league established through the Treaty of Cassius initially aimed at survival rather than revenge. Historical traces of this fights are found in Coriolanus' saga (Liv., II, 39, 2; Dionys., VIII, 14,1; Plut., Coriol., 28).
The century and a half between the Treaty of Cassius and the end of the Latin wars revolved around two pivots: defence against the Volsci and, once the need for mutual defence subsided, the clash between Rome and Latin cities.
According to historians (Diod., XIV, 102), Romans reconquered the Circeo territory in 393 b.C. In 385 b.C. the first attempt at revolt took place: some Latins, together with the Hernici and the inhabitants of Velitrae and Circeii, took advantage of Rome's difficulties following the Gallic invasion. The alliance was defeated by Aulus Cornelius Cossus.
A second uprising took place in 383 b.C.: the rebel coalition included the cities of Lanuvium and Praeneste, together with Latin and Volsci people. This time, too, Rome defeated the rebels in Velitrae.
Revolt broke out again in 340, and this time Circeii played a prominent role through its citizen Lucius Numicius, praetor of the Latin League (Liv. VIII, 3, 9.). When the Latins were defeated, Numicius fled, with what remained of his army, first to Minturnae and then to Vescia, among the Aurunci people. Manlius Torquatus finally defeated him in Trifano.
The destiny of Circeii after 338 mainly resulted from a strategic perspective and from the need to control the territory, but it was also a consequence of the three insurrections in which the colony had taken part in less than 50 years.
It was necessary to punish the disloyal colony, but also to equip it for the upcoming war against the Samnites. It is not by chance that the places showing the most similar position, fortifications and structure to that of Circeii are Artena and Norba, located along the defence line that was set up in this period.
Historical records on the 2nd century b.C. are scarce. There are instead more documents regarding the 1st century b.C., including an inscription at the Forum of Augustus commemorating Julius Caesar's father as oikistes (founding commander) of a colony by the Circeo.
In the second half of the 1st century a.D., after the infrastructural development of Lake Paola's southern shores, an imperial dwelling was planned in the area. It was built under Domitian, partly using the structures of a previous villa, and occupied a very vast area.
Tracing back the rise and decline of settlements during the Imperial age is hard: lack of documents prevents a clear reconstruction of events.