Decimus Junius Juvenalis — generally known as Juvenal — was a Roman satirist who lived in the first and second centuries AD — roughly from the time of Nero to the time of Hadrian. He's perhaps best known as the originator of the phrases, "Who will watch the watchmen?"note and "Bread and Circuses."note He lends his name to the brand of satire known as Juvenalian, which consists of scathing attacks on people and things the writer considers to be evil.
His satires are written from the point of a financially distressed member of the upper classes — the kind that in Victorian England would have been called "shabby genteel" (or in other words, a literal Impoverished Patrician). The narrator saves his bitterest vile for the upstarts, ex-slaves, and foreigners who dominated early Imperial times, but he spears almost everyone and everything: upstart women who don't sit at home and spin, gay men who think they can marry, uncaring patrons who feed their dependents plain olive oil while keeping the EVOO for themselves, the teeming, dangerous city that gets worse every day, the cruel, rapacious Emperor who cares more about the delicacies of his own table than he does about starving soldiers (probably talking about Domitian, regarded by the upper crust—somewhat unfairlynote —as the Nero of his time).
It's usually assumed that the narrator is Juvenal himself, frustrated into invective by the "moral degeneracy" of his time, but a modern Alternative Character Interpretation is that Juvenal was actually poking fun at the kind of stuffy, stuck-up old guard that would come up with these things. It's plausible, given that Juvenal (like Horace) might have been the son of an ex-slave himself. Or he might have been the son of a noble. Nobody really knows.
One previously unknown section of Juvenal's Sixth Satire - the one about women - was discovered in 1905. The section contained such sophisticated obscenity that only one man in the UK was considered erudite enough to translate it.
Juvenalian satire—satire that attacks what the author perceives as social evil through moral outrage and savage ridicule— is named for him.
His satires survived because they were critical of Pagan Rome, something the average medieval monk approved of.