Explanation: Decimation was a military punishment in the Roman Empire, used primarily in the days of the Republic, and even then only rarely. In the case of extreme cowardice or mutiny of an entire unit, the unit would be condemned to decimation - in which they would be split into groups of 10 men, and draw lots or straws. The one who drew the shortest straw was then condemned to be beaten to death by the other 9. This was seen, to the Romans, both as a punishment and a redemption, as by participating as executors, the surviving soldiers are punished, but also are resubmitting to military discipline and enforcing it in the unit.
It was considered, even by Roman standards, to be a very harsh punishment, and only a handful of examples of the punishment are known to have been carried out, and each time it was considered a major and shocking event.