Were There Mercenary Units in Ancient Greece?

From the close of the Persian Wars (449 BCE) through the ascendancy of Alexander (336BCE), conflict was a near incessant occurrence in ancient Greece. Forming a highly complex framework of rival city-states and alliances, the Greeks fought each other over several centuries. An ever-shifting patchwork of rising powers, alliances and counter-alliances dominated Greek history. It resulted in many prolonged conflicts.

It was perhaps inevitable that the scale and frequency of Greek warfare would create the ideal conditions for the use of mercenary forces. Though there were many factors, it is possible to identify key aspects governing ancient Greece and its relationship with mercenaries.

In archaic times references to epikouroi, i.e,. ‘those that fought alongside’, occur in Homer’s Iliad. Relationships were nuanced and involved social and political capital as well as monetary reward. With the flourishing of the city-states of the 5th and 4th centuries BCE, the emergence of paid and ‘professionalized’ mercenaries fully materialized.

Yet the core values of the classical city-states initially held an uneasy view of mercenaries. Homeric principles endured within Greek culture. Dominated by an elite warrior caste, war was partially ‘virtue’-based — a contest of honor where idealized heroes fought for prowess and fame. Fighting professionally could not have been more at odds with the traditional warrior ethos.

Pros & Cons of Mercenaries According to the Ancient Greeks

In its early evolution at least, the use of mercenaries was complex. Plato equated mercenaries with kidnappers, thieves, and brigands. The rhetorician Isocrates took a similarly dim view. Aristotle questioned the mercenary’s motivational and moral integrity:

“This is because citizens think it disgraceful to run away and prefer death to safety so procured; whereas professional soldiers were relying from the outset on superior strength, and when they discover they are outnumbered they take to flight, fearing death more than disgrace.”
[Aristotle, Nicomachean Ethics, 3.8]

However, the changing social and economic drivers resulting from the Peloponnesian War (431-404 BCE) ensured that mercenary usage would only grow in ancient Greece. As campaigns extended in scope, range, and tenure, both Sparta and Athens adapted. Increasingly utilizing hired fighters, several cities started to supplement their fighting capabilities.

By 401 BCE, it was marked that even reputable Greeks like Xenophon were happy to undertake well-paid mercenary contracts in the service of foreign Persian Princes.

By the 370’s BCE, the short-lived Jason of Pherae was recruiting mercenaries in considerable numbers. An exemplar to Phillip II of Macedon, Jason evidently saw the advantages:

“I have men of other states as mercenaries to the number of six thousand, with whom, as I think, no city could easily contend. As for numbers,…of course as great a force might march out of some other city also; but armies made up of citizens include men who are already advanced in years and others who have not yet come to their prime. Furthermore, in every city very few men train their bodies, but among my mercenaries no one serves unless he is able to endure as severe toils as I myself.”
[Xenophon, Hellenika, 6.1.5]

Here, in conceptual terms, was the case for using mercenaries over traditional citizens.

The wholesale adoption of mercenaries was still complicated. It was impeded by certain social and class barriers.

The socio-military framework of the classical period had formed around the primacy of the hoplite. Heavily armored citizen-warriors, they were the elite central component of ancient Greek conflict.

Fighting in tight phalanxes (units), hoplites were drawn traditionally, almost exclusively, from the citizen body. Providing their own highly prized armor and weaponry was a fundamental duty. Qualifying as a hoplite required free-born, enfranchised males to possess considerable financial commitment and conferred social kudos. To be a cavalryman was even more so, requiring huge wealth. Warfare in ancient Greece, at least in the early periods, was therefore dominated by class and wealth.

Mercenary models inevitably challenged these hierarchies and disrupted the ideals and values of traditional warrior elites. When mercenaries eventually changed the very nature of fighting, this must have jarred with existing orthodoxies. Was this a partial factor in some of the conceptual negativity that we hear voiced against early mercenaries? It seems probable. Similar ‘class shocks’ from established warrior elites have taken place in history: both the knights of Medieval Europe and Japanese Samori culture experienced similar challenges.

Xenophobia was an additional barrier to the Greek acceptance of mercenaries. Always a prominent trait within ancient Greece, this saw distrust and disdain aimed not just at ethnic ‘foreigners’, but even, in some contexts, at fellow Greeks who hailed from other ethnic tribes, cities, or regions.

Who Were the Mercenaries of Ancient Greece?

1. Greeks (Arcadians, Cretan Archers, Rhodian Slingers)

Arcadians were often cited as mercenaries. A mountainous pastoral region of the central northern Peloponnese, Arcadia was inhabited by one of the most ancient tribes of Greece. Although Arcadians were far from the sole providers of mercenaries, sources make clear that this area formed a rich recruiting ground. Other adjoining areas of the North Peloponnese, like Achaea were also noted.

In 432 BCE, the regional super-power Corinth recruited heavily in the Northern Peloponnese, gathering a force of 1600 hoplites and 400 light troops made up of mercenaries and volunteers. This force was sent to the aid of Potidaea which sought to break from Athens’ restrictive alliance, the Delian League. Corinth — an ally of Sparta — hated Athens, but at this time, it could not afford to openly break the peace. A force comprised of volunteers and  mercenaries fighting far from home was, therefore, invaluable. It allowed the Corinthians to conduct something of a proxy or ‘shadow war’, a role at which mercenaries have always been adept.

The Peloponnesian war only compounded economic and political destabilization. It saw greater numbers of displaced men from all over ancient Greece drawn to the new profession of fighting. They constituted a considerable component of the mercenary market:

“… [some men] go forth into exile and serve some tyrant elsewhere as bodyguard or become mercenaries in any war there may be.”
[Plato, Republic, 575b]

Other communities serviced demand, providing specific military specialism. Among this type were skilled missile troops who provided skirmishing and support to the traditional phalanxes of central Greece. Most famous were the Rhodians and the Cretans. Both island communities had mastered the use of specialist arms as light missile troops. The Cretans were famed for the use of the bow, which they practiced from a young age. Cretan archers fought with the Athenian Sicilian expedition (415-413BCE). Experts with the bow, they maintained their fame well beyond the Greek and Hellenistic periods.

Rhodian slingers, of Phoenician heritage, were also famously effective. They served in considerable numbers for the Athenians in Sicily, providing a body of up to 700 men. Highly effective in skirmishing on rough ground, they also kept at bay the harassing Persians who sought to destroy the beleaguered Greek mercenaries who fought their way out of enemy territory in 401 BCE.

Greeks did indeed have a history of providing mercenaries for overseas foreign service.  Ionian Greeks (from Asia Minor) had fought for foreign rulers in both Persia and Egypt before even the Persian Wars and are attested by Herodotus. Some Hellenes even fought against their mainland brothers in the service of Xerxes when he invaded Greece in 480 BCE. However, by the close of the 5th century BCE, even mainland Greeks from major city-states were fighting for money abroad. This was a marked shift, and the famous 10,000 recorded by Xenophon, who backed Cyrus the Younger in 401 BCE, drew fighters from Sparta, Athens, and many other mainland states.

“… such is now the state of affairs in Hellas that it is easier to get together a greater and stronger army from among those who wander in exile than from those who live under their own polities. But in those days, there was no body of professional soldiers …”
[Isocrates, Panegyricus, 4.168]

Perhaps no surprise that by Philip II and Alexander’s era, many soldiers (from across Greece) both fought with and against the powerful Macedonian army that invaded Persia.

But it was not just Greeks. ‘Barbarian’ mercenaries would increasingly make their own impact in ancient Greece.

On Greece’s northern borders, wild Thracian tribes had long resided. These fearsome fighters were increasingly recruited into mainland warfare. Typified as large-boned and fierce with red hair and tattoos, Thracians were both fascinating and shocking. Greeks viewed them as near savages. Split across many tribes, some Thracians were said to have never been conquered, not even by Xerxes’ vast invasion. Thrace was famously poor, and Herodotus recorded that some Thracians gave away their children to alleviate poverty.

Fierce tribal fighters, Thracians gained a reputation for savagery that may have been part stereotype and part earned. When Athens recruited a band of Thracian mercenaries to reinforce their Sicilian campaign under Demosthenes, the warriors arrived too late to be included. Not wanting to pay the latecomers, the Athenians transported the fighters and set them loose to raid. The small Boeotian city of Mycalessus paid the price, an event that shocked even war-hardened Greeks:

“They spared neither old nor young, but cut down, one after another, all whom they met, the women and children, the very beasts of burden, and every living thing which they saw. For the Thracians, when they dare, can be as bloody as the worst barbarians.”
[Thucydides, Peloponnesian War, 7.29]

Thracians were not just butchers, though. They had a considerable military impact, introducing a type of fighter called a peltast. This infantry became famous for a certain style of fighting that would change ancient Greek warfare.

3. Scythians 

Scythians were also a likely source of mercenaries, although evidence is patchy. Scythians were also fierce warriors, famed as horsemen and bowmen. The Athenians are known to have recruited Scythians in support of their military from as early as the 6th century BCE.  In the 5th century BCE, there were several mentions of Scythian archers coming to Athens.

Cultural references to Scythians come up frequently in both plays and on figure vases, though it is not clear to what degree this was actual or just a cultural fetish of the Athenians. There is considerable evidence that Athens employed a domestic Scythian police force or civic guard. However, we do not have a detailed testimony of the Scythian mercenaries’ deployment, usage, or terms of service. Still, there are tantalizing allusions:

“I suppose it was not simply [enough] to ride at the head of the “knights,” an honor not denied to the mounted archers, who ride even in front of the generals themselves?”
[Xenophon, Memorabilia, 3.3]

Glimpses is all that we get. But there could be many reasons why a xenophobic, ‘superior’ culture — like Athens — that idealized heroic warfare might not want to acknowledge the military usage of those they deemed inferior or ignoble ‘savages’.

Celts were also hired fighters in the wars of ancient Greece. In the Hellenic west, Greek colonial cities in Sicily and the Italian mainland had significant exposure to Iberian and Gallic mercenaries. Archeological evidence from known battles in Sicily in the 5th century BCE has yielded DNA to suggest that fighters were coming from as far afield as the Pillars of Hercules. These fighters included Iberian Celts from modern continental Spain.

In mainland Greece, Celts became prominent after the Peloponnesian War. By the 360s BCE, Athens and Sparta, the old enemies, formed an alliance to battle the rise of the Theban hegemony. The Spartans called in mercenary warriors, including Celtiberian horsemen, delivered by their ally Dionysius I of Syracuse of Sicily. These capable mercenary fighters delivered a masterclass:

“ But the horsemen sent by Dionysius, few though they were, scattering themselves here and there, would ride along the enemy’s line, charge upon them and throw javelins at them, and when the enemy began to move forth against them, would retreat, … if any pursued them far from the Theban army, they would press upon these men when they were retiring, and by throwing javelins work havoc with them, and thus they compelled the entire army, according to their own will, … “
[Xenophon, Hellenica, 7.1.21]

As the Celtic world increasingly intersected the Greek, ‘barbarian’ Celts became a feature of many Hellenistic armies.  Most notably, the Galatians, Celts who had crossed the Hellespont into Asia Minor in the 3rd century BCE, became a primary source of recruitment in the Eastern Mediterranean. Galatians fought for many of the successor kingdoms to Alexander’s legacy, including Ptolemaic Egypt.

Changing Times

Deep into the Peloponnesian War, Thucydides tells us of the motivational forces driving many recruited fighters into the Sicilian expedition (415-413 BCE). Something significant was happening at a socio-ethnic level:

“It was less the league than hatred of the Lacedaemonians and the immediate private advantage of each individual that persuaded the Dorian Argives to join the Ionian Athenians in a war against Dorians; while the Mantineans and other Arcadian mercenaries, accustomed to go against whatever enemy pointed out to them at the moment, were led by interest to regard the Arcadians serving with the Corinthians as just as much their enemies as any others. The Cretans and Aetolians also served for hire, and the Cretans who had joined the Rhodians in founding Gela, thus came to consent to fight for pay against, instead of for, their colonists.”
[Thucydides, Peloponnesian War, 7.57]

The underlying threads of Greek tribal ethnicity and brotherhood were increasingly being stretched to breaking point. Whether mercenaries were a cause or a symptom of this is harder to say.

Other domestic considerations played out. Maintaining Pan-Hellenic alliances (as Athens and Sparta did) took huge resources but also generated enormous revenues. Revenues that funded mercenary spending.

Sparta, always cautious of their Helot underclass, was at times reluctant to send valuable domestic manpower too far abroad, and mercenaries filled the gap. Athens, too, increasingly suffered manpower issues. Holding the sometimes reluctant Delian League together was costly but essential. The great plague of Athens  in 430 BCE only compounded issues. Securing manpower for armies and the socially lowly rank of rowers for navies became a major economic component of the lengthy Peloponnesian war.

Mercenaries were suited to fight in campaigns far afield for extended periods. Not something traditional citizen militias – with civic and economic commitments – were always happy to do. At a societal level, too, changes were inevitable. The previously unchallenged prowess of the classical hoplite was also changing.

Among several changes was the rise of the mercenary peltast, a type of lightly armed javelin-throwing troop, expert in mobile skirmishing and fighting on rough ground. Lighter than armored hoplites, they were considerably better armed than the lowest classes of peasant fighting troops. Peltasts were named after the small shield or pelte that they carried. They carried several javelins and were a sort of hybrid between missile and light troops.  Originating with the Thracian and Paeonian style of fighting, peltasts offered the southern Greeks a new style of highly mobile warfare.

Though it started as an ancillary skirmishing arm to the phalanx, later, entire forces would be made up of these highly effective troops. Many Greeks adopted their style of fighting, and their dynamic, ‘beat and retreat’ tactics would change the nature of battles. It shocked the more static and traditional orthodoxy of hoplite warfare and presumably the hoplite classes themselves. By the 4th BCE century, peltasts were a common component of many armies. The Athenian strategos Iphicrates optimized the equipment and tactics of his peltasts. In 391 BCE, as part of the Corinthian War, Iphicrates used a sole body of mercenary peltasts to outmaneuver and maul a Spartan hoplite force. Though hoplites would always endure, peltasts ushered in a new dimension to Greek warfare, serving Alexander and his successors across the Hellenistic world.

Traditionally, mercenaries were not accepted and jarred with the idealized views of ancient Greek warfare. Stigmatized, it would seem these opinions started to shift as mercenaries became more commonplace throughout ancient Greece.

Mercenaries proliferated, particularly during the Peloponnesian war. Driven by changing economic and social realities, this continued apace into the Hellenistic period. Greeks themselves would increasingly become mercenaries, both at home and abroad.

Mercenary usage signaled profound changes to the social and military fabric of ancient Greece. Paid fighters changed society, breaking down static traditional orthodoxies that had seen propertied citizen militia as the near-exclusive mainstay of Greek armies.  This powered real changes in the nature of battle as both foreign and domestic mercenaries facilitated innovations in tactics and fighting.

Though we may not always hear in detail about their organization, conditions, and tactics, mercenaries increasingly became an important component of warfare in ancient Greece.