There was once a military formation that was seemingly immortal. No matter how many were killed in battle, there appeared to be as many men left as when the battle began.

These remarkable soldiers were the Immortals, the crack troops of the Persian army. The Persian Empire came into being in about 560 BC and its army was truly impressive. Hundreds of thousands of troops could be summoned by the Emperor, but the 10,000 Immortals were the finest. They were dressed in the best armour available and carried magnificent weapons.

Their peculiar name came from the fact that whenever an Immortal died, another man was at once promoted from the normal ranks of the army. In this way the Emperor ensured that he always had 10,000 first class troops to send into battle. It also gave the illusion that the Immortals were truly immortal.