The Laws of War in Ancient Greece

Whether between Greek city-states or against external powers such as Persia, ancient Greece was a hotbed for war and the exercising of power. Yet, among the clatter of swords and shields in warfare, there still existed certain laws.

Perhaps the earliest and best-known example of a practical statement about international relations and warfare comes from the ancient Greek historian Thucydides.

In his book, History of the Peloponnesian War, he writes about the Melian dialogue, which tells the story of the Athenian invasion of Melos in 416 BC. Melos, a small island in the Aegean, wanted to maintain its stance of neutrality and avoid joining the Athenian empire.

Thucydides relates the negotiations between the Athenians and Melian leaders, writing that the Athenians gave the Melians a choice to either become a subject of Athens or resist and be annihilated.

According to Thucydides, the Melians claimed that justice was on their side as the non-aggressor, but Athenians dismissed these arguments from justice as irrelevant. They replied with a statement which many experts believe to be Thucydides’ own view: “We both alike know that in human reckoning the question of justice only enters where there is equal power to enforce it, and that the powerful exact what they can, and the weak grant what they must.”

Thucydides’ presentation of inter-state dialogue and relations has raised questions about the effectiveness of the ancient Greek laws of war. The vision of honorable ancient Greek laws of war has been slightly tarnished, too, by the massacres of non-combatants and other gross violations of modern-day humanitarian protections that occurred frequently in the Classical period.

There was, in fact, a partially effective law of war in ancient Greece, but this did not include the kind of humanitarian ideals we see today. Instead, it focused on protecting sacred objects and observances.

There are several examples of treaties claiming to regulate the conduct of warfare. However, the ancient Greek law was mostly an unwritten set of norms arising from Greek custom. Scholars claim there is one formal agreement from the Classical period that addresses conduct in war scenarios. Theoretically, it would have applied to most of Greece, but it was supposedly ignored in practice.

The Amphictyonic Council was an association comprised of the majority of Greek city-states which was formed to protect and oversee the oracle and sanctuary at Delphi.

According to the fourth-century politician Aeschines, members swore an oath “not to lay waste to any city belonging to the Amphictyonic Council, nor keep it from using any spring, neither in war, nor in peace; but if anyone violate these oaths, to take the field against him and lay waste to his cities.”

The oath was broken often, and most scholars say it was never enforced according to its terms, albeit a few attempts to fine violators were made.

The law of war in Archaic and Classical Greece was mostly informal and based on custom, arising from shared norms and practices rather than encoded laws and treaties.

How were the laws of war enforced in ancient Greece?

In the uncommon case where multi-stage agreements were employed, some parties to the agreement may have tried to punish violations, possibly through the issue of a fine, as the Amphictyonic Council did. However, direct sanctions by third parties were rare.

Although the evidence is inconclusive, it appears it was acceptable for the states of ancient Greece to retaliate in kind. In some cases, states argued that actions taken that were contrary to the laws of war were enough of a justification for reprisal. For example, the Boeotians did away with the custom of the victor in battle handing back the dead to their enemy for proper burial. This was because the Athenians violated the sacred sanctuary of Delium in their territory.

Thucydides discusses the legality of reprisals in his presentation of the trial following the siege of Plataea. In 431 BC, a group of Thebans attacked Plataea, and in so doing, they contravened a peace treaty and violated the prohibition against attacking a state during a religious festival.

The Plataeans beat the invading Thebans and took more than one hundred prisoners, whom they later executed. A few years later, the Thebans, along with their Spartan allies, attacked Plataea. After a lengthy siege, the Plataeans surrendered on terms brought by a herald: “If they are willing, voluntarily, to turn their city over to the Spartans and accept them as judges, they would punish only the guilty, but no one contrary to justice.”

At the trial held by the Spartan judges, the Plataeans argued that their murdering of the Theban prisoners was justified as a reprisal: “The Thebans have committed many other crimes against us, and you yourselves know of their latest crime, the reason we are now put to this ordeal. You see, we took action against them when they attacked our city during a truce, and, besides that, during a holy month. We did so properly, in accordance with a universal law that makes self-defense against an aggressor a divinely-sanctioned act; and now, it would not be seemly if we suffer because of the Thebans.”

Sadly, it is not known whether this argument would have been recognized as legitimate in ancient Greece because the Spartan promise of a fair trial turned out to be a lie, aiding their war efforts. The Spartan judges deemed the Plataeans to be long-standing allies of the Athenians. Therefore, for the Spartans, they were guilty.

There are other sources which suggest reprisals were not permitted in ancient Greece at least in the case of norms based on religious customs.

The ancient Greek historian Polybius wrote that destruction of sacred buildings and objects was not tolerated even in retaliation and gave examples of commanders, most notably Alexander the Great, who acted out his vengeance on states that committed sacrilege against them but carefully avoided destroying sacred objects themselves.

There are two tales told by the ancient Greek historian Herodotus, written in the fifth century BC, which are slightly harder to untangle.

To atone for having killed Persian ambassadors, who were entitled to immunity under the laws of war, the Spartans sent two volunteers to offer themselves to Xerxes, the Persian king. However, Xerxes refused to take the ambassadors’ lives, saying that “he would not behave like the Spartans, who, by murdering the ambassadors of a foreign power, had broken the law of all men, and that he would not be guilty himself of the same crime they had committed.”

Later in the war against the Persians, a Spartan commander was horrified by his advisor’s suggestion that he mutilate the body of a noble Persian in retaliation for the Persians’ previous impaling of a Spartan king.

These two examples suggest a custom against reprisals, but the fact that others urged the two commanders to take revenge highlights that the custom was not strictly adhered to.