The son of Aruns, who was the brother of L. Tarquinius Priscus, was born after the death of his father ; and as Demaratus, the father of Aruns, died shortly after the death of his son without knowing that his daughter-in-law was pregnant, none of his property was left to Egerius, from which circumstance, according to the legend, he derived his name. When the town of Collatia was takon by his uncle Tarquinius Priscus, Egerius was left in command of the place, and henceforth received, according to Dionysius, the surname of Collatinus (though this name is usually confined to his son L. Tarquinius Collatinus). Egerius was afterwards sent against Fidenae in command of the allied forces of Rome. (Liv. i. 34, 38 ; Dionys. iii. 50, 57, comp. iv. 64.)