Lake Regillus.
Fought B.C. 497[B.C. 497], the first authentic date in the history of Rome. The details handed down, however, belong to the domain of legend rather than to that of history. According to the chroniclers, this was the last attempt of the Tarquinian family to recover the throne of Rome. They were, however, totally routed by the Romans, under Aulus Postumius, and all the sons of Tarquinius, and his son-in-law, Mamilius, were slain in the battle. The legend avers that the Romans, when victory was trembling in the balance, found at their head two young men on white horses, whom they claimed to be Castor and Pollux.