Pollice verso (also referred to as verso pollice) was a gesture condemning the defeated gladiator in ancient Rome to death. Contrary to common beliefs and the image disseminated by cinematography, it is uncertain whether in ancient Rome this gesture was actually in the form of a thumb pointing downwards
The phrase pollice verso means literally “an inverted thumb”. In the name of the gesture, however, there is no direct indication of where the thumb is directed.
Determining the exact appearance of the “gesture of death” is difficult because there are no ancient iconographic sources on this subject. We can only base on written sources, but these are few, and the gesture is usually too general.
A similar phrase (converso pollice), uses Aurelius Prudentius (Libri contra Symmachum). Converso pollice can be explained like verso pollice (“thumb twisting”).
Quintilian (Institutio Oratoria, XI.1.119) mentions the infesto pollice gesture, which can be literally translated as “unfriendly / hostile thumb”, does not tell us anything about the exact laying the thumb. Besides mentioning it as an oratory gesture, no reference to gladiatorial fights.
The same wording (infesto pollice) is repeated in Anthology Latina (415.27-28), already in the context of the gladiator’s battle in the arena. The text evokes the image of the crowd waving the “hostile thumb” towards the defeated gladiator. Unambiguously identifies infesto pollice with a gesture of death condemnation, but still does not describe the appearance of the gesture in sufficient detail.
Pliny invokes the phrase pollices premere (Natural History, XXVIII.25), which can be translated as: “thumb pointing down”, “thumb squeezed inside the palm of hand” (surrounded by other fingers), or “thumb pressed to your hand” (from the outside). The gesture is described as a gesture of acceptance.
According to the present state of research, the hypothesis seems to be that the thumb pressed against the index finger (hand curled into a fist) signified the demand for grace, while the thumb protruding above the folded fist (the direction seems to have no meaning) meant a deadly blow. The winner made the blow with both hands, thrusting the sword in the back in the area of the left shoulder or in the heart, between the left collarbone and the neck. The gesture of the hand meant the task of such a blow by thrusting the blade all the way to the hilt itself.
Martial also mentions in the Liber spectaculorum about the habit of waving a handkerchief or shouting in order to pardon a defeated gladiator.