The Ancient Roman military brought the Empire into being, and its soldiers had far-reaching reputations for their discipline and skill. A look at the severity of punishments for wayward enlisted men goes a long way to explain this — the Roman officers could be as brutal to their own men as they were to their opponents.
Soldiers had to obey their superiors — the image shown here is of a Roman Emperor addressing his men before a battle, and you can see how attentive they look. As the second-century BCE historian Polybius records, bludgeoning to death was standard punishment for a wide variety of infractions. Falling asleep on duty? Bludgeoning to death. Abandoning a post? Same. And the same applies to falsely reporting about one’s bravery to gain honor. “Some men who have dropped a shield or a sword or some other arm in the heat of battle throw themselves recklessly into the midst of the enemy, hoping to regain possession of the weapon they have lost or resigning themselves to escape, by this death, certain disgrace and taunts of their friends and relatives,” writes Polybius.
And it is Polybius who best describes the Roman practice of “decimation” — we have our cognate word from this term. If a large group of soldiers abandoned their positions in battle, once the fighting was done, the officers would take the entire group and select one out of every ten men by lottery to be publically and mercilessly beaten to death.
Source(s): Image from Scene 10 of @trajans-column.org. pp 247-248 of _As the Romans Did_ Jo-Ann Shelton. Polybius, _History of the World, excerpts from book six.