Decimus Iunius Iuvenalis, known in English as Juvenal, was a Roman poet active in the late 1st and early 2nd century AD, author of the Satires. The details of the author's life are unclear, although references within his text to known persons of the late 1st and early 2nd centuries AD fix his terminus post quem (earliest date of composition).
"A healthy mind in a healthy body."
"Be rich to yourself and poor to your friends."
"Who will guard the guards themselves?"