Cassius Dio Cocceianus, Dio's Rome, Volume 6
“ The story of Rome follows. Aventinus begat Numitor and Amulius. Numitor while king was driven out by Amulius, who killed Numitor's son Ægestes in a hunting party and made the sister of Ægestes, daughter of the aforesaid Numitor, Silvia or Rhea Ilia, a priestess of Vesta, so that she might remain a virgin. He stood in terror of an oracle which foretold his death at the hands of the children of Numitor. For this reason he had killed Ægestes and made the other a priestess of Vesta, that she might continue a virgin and childless. ”
