magnum opus
Somebody's greatest work — the one they will be remembered for.
“The novel took eleven years and is generally considered her magnum opus.”
“He spoke about the project as his magnum opus, which was either confidence or a way of explaining why it was four years late.”
“Critics settled on the second symphony as the magnum opus, a judgement the composer resented for the rest of his life, since it quietly reclassified everything he wrote afterwards as an appendix.”
The Latin is plain — magnum opus, great work — and opus is the ordinary Roman word for a piece of finished work, the same word that still numbers a composer's output.
Its first specialised use in English was alchemical. The Magnum Opus, the Great Work, was the whole process of producing the philosopher's stone: a sequence of stages that would take a lifetime and, in the nature of things, was never completed by anyone.
The literary sense took over in the eighteenth century and kept a little of the alchemical flavour. A magnum opus is not just a good book. It is the long, difficult, career-defining one, and calling something a magnum opus while its author is still alive is a fairly heavy thing to say.
Horace, Virgil and Cicero, still quoted in the original.
- 01
carpe diem (idiom)
Seize the day — make use of today rather than counting on tomorrow.
Horace, Odes 1.11.
- 02
tempus fugit (idiom)
Time flies — said when far more of it has gone than you expected.
Virgil, Georgics.
- 03
memento mori (idiom)
A reminder that you are going to die, and that this should change how you spend the time.
The warning in the chariot.
- 04
in vino veritas (idiom)
People say what they actually think once they have had a drink.
Pliny the Elder.
- 05
festina lente (idiom)
Make haste slowly — move quickly, but never faster than you can do it properly.
Augustus' favourite motto.
- 06
to err is human (idiom)
Making mistakes is part of being a person, so a mistake alone is not a scandal.
Cicero, then Pope.
Last updated August 3, 2026