Decimation - if you were to look it up in the dictionary you might find words to the effect of "to destroy or kill a large proportion of (e.g. a plague decimated the population)". In the Thesaurus you will find synonyms such as 'annihilation', ' cataclysm' or 'devastation'; all of which sounds pretty apocalyptic. But was it always this way? Has modern usage assigned a meaning that is far bigger than the original intent?
Well - the short answer is "yes", but when was there ever any fun in giving a short answer when you have a long one to hand, as it were.
The word decimation - as you might not be surprised to learn - originates from the Latin for ten (i.e. decem). In its original form, decimation was a form of punishment used to instill discipline within the Roman Army from the fifth century BC until the early Imperial times of the first century AD, and which even made the odd appearance in much later times - but more of that later.
So what was decimation all about? Well, in essence it was a spectacularly brutal exercise that must have been an incredibly effective deterrent to any unit that was considering desertion in the heat of battle or mutiny against their commanding officers.
In summary, the procedure - once enacted - was as follows: a cohort (typically around 480 men) was divided into groups of ten. Each group then drew lots with the loser then being executed by the other nine - usually by means of stoning or clubbing to death.
Watching someone being executed by means of a hangman or similar must have been bad enough, but actually having to do the killing yourself must have been horrendous. The poor sod who drew the short straw might well be your best friend - someone with whom you had joined up many years before, trained with, fought with, perhaps even saved your life on occasion. At the very least it would be someone you shared a tent or barracks-room with. Someone with whom you had forged an incredibly strong bond of trust and loyalty. And now you had to crush his skull with a rock.
For the rest of the unit, that was not the end of the matter, though their fate was by no means as bad. They were made to live off barley instead of wheat rations and forced to camp outside the walls of the fort for a few days which, if on campaign, must have carried its own dangers.
I can well imagine that the threat of this punishment must have gone a long way to keeping legionaries in line when it came to facing down overwhelming odds in battle. Better to fight and die with honour than live with disgrace and the threat of decimation.
How often was it used? Not very, in a nutshell. The earliest recorded instance occurred in 471 BC where, after the army had been scattered by the Volsci tribe, the consul of Rome ordered that the officers who had thrown away their weapons would be whipped and beheaded and that the rank and file would be decimated.
Another example occurred during the Third Servile War in 71 BC (cue cries of "I'm Spartacus and so's my wife".... er.... hang on). Following early victories for Kirk Douglas' slave army, the Roman Commander - Marcus Licinius Crassus - dished out the punishment to which a number of contemporary historians then attributed his subsequent success. Hollywood left that bit out of the film, though I don't know why as it would have added to the drama quite nicely.
Although the practice was eventually outlawed in the later Roman Empire, there have been a few recorded instances in more recent times. For example, in 1642 during the Thirty Years' War, Colonel Madlon's cavalry regiment (of the Holy Roman Empire) fled the Battle of Breitenfeld (near Leipzig) without a shot being fired. Afterwards the commander, Arch-Duke Leopold of Austria, erased the regiment from official lists, condemned the officers to be beheaded and 90 of the the soldiers were decimated with the survivors being discharged from the army.
So whilst decimation only really meant that 1 in 10 were actually killed, the impact on those involved must have felt pretty cataclysmic all the same.