In modern parlance, the term ‘decimation’ has come to refer to a military force or general population suffering an extreme reduction in numbers, or more widely to convey general destruction. However, the term decimation refers to a very particular punishment during antiquity, from the Latin decimatio: to reduce by a tenth.
Decimation was one of the ultimate forms of military discipline for military units of the early Roman Republic accused of cowardice, mutiny, insubordination or other derelictions of duty. The men to be punished would be split into groups of ten, then made to draw straws. For each group, the man that drew the shortest straw would be beaten or stoned to death by the remaining nine.
The earliest known use of decimation comes from 471 BC, during the fledgling Roman Republic’s early expansionist war against the Volsci tribes of central Italy. The Roman historian Livy records that after his army was routed in battle by the Volsci, consul Appius Claudius Sabinus Regillensis ordered his troops to be punished by decimation. After those that had deliberately thrown away their weapons during the retreat were singled out, whipped and beheaded, the remainder were formed into groups of ten and made to draw lots. One in ten were then executed, although it is not recorded whether their fellows were forced to carry out the killing.
The Greek historian Polybius detailed how the practice worked during the 3rd Century BC. When large groups of men required punishment, meaning that outright execution of them all was impractical and would hamper the ability of the army to function, one-tenth of the group considered guilty of cowardice would be decided by a lottery system, before being bludgeoned to death. The practice appears to have been used by Greek as well as Roman commanders, with Alexander the Great recorded as using decimation to punish a corps of 6,000 soldiers.
Julius Caesar threatened to employ decimation against the 9th Legion during his civil war against Pompey, but ultimately didn’t follow through with his threat. Contemporary Mark Antony, however, did use the punishment during his failed invasion of the Parthian Empire.
The archaic practice appears to have largely fallen out of favour during the Roman Republic period, but was revived by Marcus Licinius Crassus in 71 BC as he struggled to contain an uprising of around 120,000 slaves, spearheaded by a large number of gladiators and commanded by Spartacus. Known as the Third Servile War, the uprising initially defeated two Roman expeditions sent to quell the rebellion. As a result, the Senate charged Crassus, then the wealthiest man in Rome (and, translated to modern terms, one of the richest men in history), with ending the slave revolt.
Commanding up to 48,000 Roman legionnaires as well as auxiliary forces, Crassus is recorded as making use of decimation to keep his extensive army in line, as well as to punish their failure after an early defeat to Spartacus. Several historians have argued that by establishing himself as more dangerous to his troops than the enemy, he instilled in them the resolve needed to inflict a string of defeats on the rebel gladiators. This culminated in the final defeat of the rebel slaves at the Battle of Silarius River, killing over 36,000 and crucifying a further 6,000 more.
The Emperor Macrinus introduced a less harsh version known as centesimatio during the 3rd Century AD, where only one man in 100 was killed. The practice was banned in the Byzantine Empire during the reign of Flavius Tiberius Mauricius due to its impact on morale and fighting effectiveness.
While there are no reliable accounts of decimation being used for over a thousand years since the fall of the Western Roman Empire, it was revived twice by the Holy Roman Empire during the Thirty Years War (1618-1648). After a cuirassier regiment fled during the Battle of Lutzen in 1632, a court martial ordered their commanding officer, ten officers and five troopers beheaded. The remaining cavalry troopers were decimated, with one in every 10 hanged.
Ten years later, another cavalry regiment fled without making contact with the enemy during the Battle of Breitenfeld, triggering a mass route of Imperial cavalry units and handing a decisive victory to Swedish forces. Six full regiments were assembled in Prague, where their senior officers were beheaded, ensigns were hanged, and the soldiers decimated.
Decimations were later used during the First World War. Tunisian colonial soldiers in the French army that refused to carry out an attack were ordered decimated in 1914, with 10 men being executed. Accounts of decimation by an Italian general emerged in 1916 following the Battle of Caporetto, however some historians argue these were specific executions of individuals rather than a punishment across entire units. The mutinying 141st Catanzaro Infantry Brigade, however, was confirmed to have been decimated in May 1916.