what id the origin of thumbs-up signal?

What is the origin of the “thumbs-up” and “thumbs-down” commonly used to mean good or ok, and bad or not-ok respectively?

Was it Roman emperors signalling the fate of gladiators?

I did a search of Cecil’s columns figuring that this has been tackled before but i came up with nothing.

I always assumed it originated with Fonzie!

::Ducks::

According to gladiator documentary on the “Gladiator” DVD, it was originated by some early gladiator film director (specific person not named) and his impression of the signal from the emperor (or other games sponsor) for the victor to kill or spare a yielding fighter. The gesture was described in Roman literature, but not very well.

Of course, this may be BS, so YMMV.

Although early gladiator flicks brought the thumbs up-thumbs down motif widespread fame, it was preceded by (and believed derived from) French painter Jean Leon Jerome’s 1874 gladiator painting “Pollice Verso” (literally, “Thumbs Down”).

I remember reading that the “thumbs up” was the sign for “kill him” in Roman times, contrary to expectation. Any Dope on this, or strictly UL?

Apparently, Cecil addressed this in his column on Why do we nod our heads for “yes” and shake them for “no”?:

(bolding mine)