Decimation was a form of extreme military discipline imposed by officers in the Roman Army. Literally meaning "removal of a tenth," this punishment was assigned to mutinous or cowardly soldiers. Those selected for punishment were divided into groups of ten; each group cast lots, and the soldier on whom the lot fell was executed by his nine comrades, often by stoning or clubbing. In addition, the remaining soldiers were given rations of barley instead of wheat and forced to sleep outside of the Roman encampment.
Because the punishment fell by lot, all soldiers in the selected cohort were eligible for execution, regardless of rank or distinction. As a result, the threat of decimation inspired fear and resolve into the Roman Legions. In addition, troop morale often increased dramatically after a decimation. However, because a decimation significantly reduced the troop strength of an army, the punishment was rarely utilized.
The earliest documented decimation occurred in 471 B.C. during the Roman Republic's early wars against the Volsci and is recorded by Livy (Ab urbe condita, ii.59). The practice was revived by Crassus in 71 B.C. in the Third Servile War against Sparticus. It remained popular during the Roman Empire, and Seutonius records that it was used by Augustus in 17 B.C. (Augustus, 24).
In current usage, decimation refers to an extreme reduction in the number of a population or force, usually far greater than the one tenth specified above. It perhaps more frequently describes an occurrence in which closer to one tenth of the original number remains, rather than is lost.
