And I thought 'rule of thumb' had something to do with the Romans, and the gladiatorial arenas, and if the Emperor or whoever was in the seat of the 'main dude' decided that the beaten opponent should be 'topped' then he gestured with his thumb in a downward pointing fashion.
There has been debate over whether 'thumb-up' or 'thumb-down' meant death? Experts now think that 'thumbs-up' meant to kill (although it's more complicated than that):
“We don’t have videotapes of people from antiquity. We have some sculptural references but it’s mostly verbal references,” says Anthony Corbeill, a professor of Latin at the University of Virginia, who wrote a book on
gestures in ancient Rome. “Sparing is pressing the thumb to the top of the fist and death is a thumbs-up. In other words, it’s the opposite of what we think.”
Historical confusion about that thumb-pressing gesture exposes just how difficult it can be to track the evolution of body language. The Latin term for the gesture of approval, Corbeill explains, is pollices premere, which means “press your thumbs” and has been described by Pliny the Elder as a common gesture of good wishes. But that doesn’t help much. “The verb premere in latin is just as ambiguous as ‘press’ in English,” he says. “A thumb can press or be pressed, it works both ways.”
Corbeill located an example of what exactly the gesture might look in Nîmes, in southern France, when he
found an appliqué medallion that shows a scene from a gladiatorial battle. “What’s great about these is that they often have text accompanying them, so what you see very clearly is two gladiators fighting to a standstill. There’s two referees around them breaking up the battle and up above it says, in Latin,
STANTES MISSI, which means ‘let the men who are still standing be released,'” he says. “And right underneath, one of the referees is pressing his thumb. He’s got a fist with his thumb pressing down on it.”
So the crowd didn’t the decide the fate of the gladiator, but rather a referee in the arena who would use that gesture to communicate a decision about whether the fighter should be spared. A second relief in Munich from the 1st century A.D. confirmed Corbeill’s conclusion, showing the same gesture in the same context, and a 4th century riddle also implies that meaning when it describes a storm being kept at bay by a thumb “pressed” to keep liquid in a straw.
And what about the gesture for the death blow? Here things are in some ways even trickier, as there is no definite visual representation of the movement.
Two textual descriptions of a gladiatorial battle, from the poets Juvenal and Prudentius, both reference the
pollice verso or
pollice converso, the “turned” thumb, as the signal for death. “This is the reason often historians have thought of the thumb turned down,” Corbeille says, but there’s evidence that the turn would have gone in the other direction.
For example, the word for turning also means turning a limb in question on the joint, but doing the modern thumbs-down gesture involves turning the wrist, not the thumb. “‘Turning the thumb’ is turning the thumb up [from that closed fist],” he says, “and you’ve got the ‘up’ gesture.”
Another reason we know the thumbs-up was the kill signal was a gesture known as the infestus pollex or hostile thumb, which is mentioned in texts but, again, isn’t pictured. In antiquity, says Corbeill, “the thumb was hostile in the same way the middle finger was hostile, and it was a threat, just like it is now.”
CONTINUED:
https://time.com/4984728/thumbs-up-thumbs-down-history/