Suetonius,
The Lives of the Twelve Caesars…
“ In this period died, in the eighty-sixth year of her age, Livia Drusilla, mother of the emperor, and the relict of Augustus, whom she survived fifteen years. She was the daughter of L. Drusus Calidianus and married Tiberius Claudius Nero, by whom she had two sons, Tiberius and Drusus. ”
