A unit selected for punishment by decimation was divided into groups of ten; each group drew from lots or stones (named Sortition), and the soldier on whom the lot fell was executed by his nine comrades, often by stoning or clubbing. The remaining soldiers were given rations of barley instead of wheat and forced to sleep outside the Roman encampment in the followers camp. Because the punishment fell by lot, all soldiers in the group were eligible for execution, regardless of the individual degree of fault, or rank and distinction.
The punishment was later brought back to the Roman military by Marcus Crassus during the Third Servile War. Crassus used this punishment on his own legions, to ensure that his men feared him more than the enemy. 12,000 men were involved in the disgraceful operation under the command of Mummius, one of Crassus' tribunes. There were 10,000 survivors, and they were divided into groups of ten. 1,000 soldiers were killed off.Crassus' entire army was forced to witness the deaths of their comrades as warning to any others who considered disobedience.