Who were the legendary Persian Immortals?

The Persian Immortals are first mentioned in the Achaemenid military under the reign of Cyrus the Great in the 6th century BCE.

He was the founder of the Persian Empire and was the one that recognized the need for a reliable and elite force to defend his expanding realm.

This force became known as the Immortals: a unit of 10,000 soldiers who were always kept at full strength.

Whenever a soldier died, retired, or was incapacitated, he was immediately replaced by another carefully selected warrior.

This was meant to guarantee the unit's constant size. This gave rise to their name and the aura of invincibility that surrounded them. 

Their importance grew even further under Darius I, who reorganized the Persian military to strengthen his hold over the empire.

By 522 BCE, during Darius's reign, the Immortals had become the king’s personal force, guarding his capital at Persepolis.

At the top of the Immortals stood a commander, often a close advisor or relative of the Persian king.

One such leader was Hydarnes, who led the Immortals during the Greco-Persian Wars.

Beneath the commander, the Immortals were divided into groups, each consisting of 1,000 soldiers. 

Recruitment into the Immortals was a highly selective process. Most soldiers came from Persian or Median noble families, as loyalty to the king and the empire was a primary qualification.

Only the finest warriors, both in skill and devotion, were chosen to join this elite force.

The rigorous selection process ensured that the Immortals were composed of soldiers who could be trusted to protect the Persian king and carry out his military campaigns without question. 

Their primary weapon was a six-foot-long spear with a sharp spearhead, featuring a counterbalance shaped like fruit, often an apple, which led to their nickname, the 'apple-bearers'.

Additionally, they carried short swords or daggers and sometimes a sagaris, a light battle-axe.

In addition to the spear, each soldier carried a short sword, or akinakes, which was used in close combat.

The akinakes was a double-edged weapon that gave the Immortals an advantage when engaging enemies at close range, particularly after formations had broken. 

The Immortals also carried wicker shields covered with leather, known as gerrha, which were lightweight but strong enough to provide protection in battle.

These shields were designed to absorb blows without sacrificing mobility, which was an important factor in their military tactics.

Unlike the heavy bronze shields used by Greek hoplites, the gerrha allowed the Immortals to move quickly and maintain their formations.

While it offered protection against arrows, it was less effective against heavier weaponry.

Along with their shields, they wore scale armor made of overlapping plates of bronze or iron, resembling fish scales.

It offered protection and much more freedom of movement than solid metal armor.

Finally, they wore tiaras or felt caps as headgear, which varied in form but generally served to protect against wind and dust. 

Tactically, the Immortals excelled in their use of tight formations and disciplined maneuvers.

They often fought in a phalanx-like formation, similar to their Greek counterparts, but with more emphasis on mobility.

Their ability to hold the line and adapt quickly to changes on the battlefield was at the core of their training.

The Immortals employed strategies that focused on overwhelming their enemies with coordinated attacks.

Their archers, who were part of the unit, played a critical role in softening enemy lines before the main assault.

These archers fired from behind the front ranks, sending a barrage of arrows into opposing forces while the spearmen advanced. 

The Immortals were also key players in the conquest of Egypt in 525 BCE under Cambyses II.

As the Persian Empire sought to expand its influence, the Immortals were deployed in major offensives against neighboring kingdoms.

While in Egypt, they supported Cambyses in his swift victory over the pharaoh Psamtik III at the Battle of Pelusium.

Specifically, their discipline and the fear they inspired contributed to the relatively quick subjugation of Egypt.  

Also, the Persian Immortals famously appeared in the Greco-Persian Wars, particularly during the reign of Xerxes I.

In 480 BCE, during the second invasion of Greece, the Immortals were at the forefront of the Persian army as it marched to subjugate the city-states.

In particular, at the Battle of Thermopylae, they were sent against the Spartan-led Greek forces in an attempt to break through the narrow pass.

Though they encountered fierce resistance and even faced heavy losses. 

Another prominent engagement occurred in the same campaign at the Battle of Plataea in 479 BCE.

After the Persian defeat at Salamis, Xerxes withdrew most of his forces, but he left the Immortals and other elite units behind under the command of Mardonius.

During the decisive confrontation at Plataea, the Immortals fought valiantly but ultimately could not prevent the Persian defeat.

Regardless of their renowned skill and fearsome reputation, the Greek forces, leveraging their knowledge of the terrain and united under a common cause, secured a surprise victory. 

The last mention of the Immortals was during the invasion of Persian by Alexander the Great.

Specifically, at Gaugamela, the Immortals were positioned in the center of the Persian line, alongside King Darius III and other elite units, including Greek mercenaries and Persian heavy infantry.

Despite their strength and ideal positioning on the battlefield, they faced a well-coordinated attack by Alexander's forces which practically avoided them.

Instead, Alexander led a decisive cavalry charge that broke through the Persian center, leading to chaos and eventual defeat for Darius III.

Ultimately, the battle ended with a decisive victory for Alexander, and effectively sealed the fate of the Achaemenid Empire. 

As such, the fall of the Achaemenid Empire in 330 BCE led to the eventual decline of the Persian Immortals.

The Persian Empire's military structure, including the Immortals, collapsed. While some remnants of the Immortals may have continued to serve under local Persian rulers, their significance diminished rapidly.

This is because Alexander's conquests introduced new military tactics and structures, which overshadowed the traditional Persian units.

The Immortals, once the pride of the Persian army, could not survive in the changing nature of warfare that emerged during the Hellenistic period. 

However, the image of the Persian Immortals has evolved into something larger than life, often bordering on myth, in the modern memory.

This is due to the ancient sources, particularly Herodotus, who portrayed them as an invincible force that never lost its numbers or strength.

This portrayal contributed to their legendary status. However, this image likely exaggerated their abilities.

The Immortals were highly trained and disciplined, but they were not unbeatable.

At battles such as Thermopylae and Plataea, they faced determined resistance and suffered significant losses, showing that they were not invulnerable.

Their reputation, though deserved, was shaped by both Persian propaganda and the fear they inspired in their enemies.