Arruns Tarquinius was the younger son of Demaratus of Corinth, who migrated to the Etruscan city of Tarquinii in the seventh century BC.
He died shortly before his father, leaving his wife pregnant.
The child came to be called Egerius, meaning "the needy one.
[4][5][3] After subduing the Latin town of Collatia, Tarquin placed his nephew in charge of the Roman garrison there.
[6][7][3] Egerius was the father of Lucius Tarquinius Collatinus, one of the first Roman consuls in 509 BC.