Battle of Plataea 479 BCE: Spartan Strategy and Greek Alliance Crush Persia

The town of Plataea lay south of Thebes, on the Boeotia plain. Early in the Classical Age, in the late fifth century, the city refused to come under Thebes’s control and asked Sparta if it could join the Peloponnesian League. Seeing an opportunity to continue to destabilize central Greece without sending forces to the north, Sparta suggested that Plataea make an alliance with Athens to prevent Thebes from taking it over. Plataea and Athens formed an alliance, and when Thebes moved south against Plataea to force it into the Peloponnesian League, Athens sent an army.

The city of Corinth agreed to arbitrate, and in the settlement, Plataea was not required to join the league, and in fact no city was required to join unless they desired it. After the agreement, the Athenians left and were soon attacked by a Theban force, which they defeated. With their victory, Athens cemented its alliance with Plataea and guaranteed the latter’s freedom. Years later, when Athens faced Persia at Marathon in 490, Plataea sent all of its troops, 1,000 men, to fight. Accorded the position of honor, it helped Athens win the battle and were recognized in the victory memorial.

After the Persian victory at Thermopylae, Plataea and Thespiae, the cities of Boeotia that did not surrender, were destroyed. After the Battle of Salamis, Xerxes fled with most of his army, leaving his capable general, Mardonius, behind. After the defeat at Salamis, Mardonius urged Xerxes to remain in Greece, but instead he was appointed by Xerxes to take Greece the following year. Mardonius retreated from Attica and made Thessaly his winter base. In the spring, he subdued Macedon, whose king, Alexander I, informed Athens of the Persian plans. With a force of over 200,000 troops, Mardonius made Thebes his base of operations in 479.

During the winter after Salamis, the Greeks debated their strategy. The Spartans and their allies refused to move beyond the Peloponnese, while the Athenians refused to commit their fleet to the allied cause. Knowing that the Persians did not have a fleet that had sailed to Samos, the Peloponnese did not have to worry about an amphibious assault and therefore could wait. The Athenians, who were not protected by the isthmus wall, grew concerned over the Persian control of northern Greece. Mardonius sent a delegation led by Alexander of Macedon to offer terms to Athens. According to the historian Herodotus, the Athenians refused the offer but made sure that a Spartan delegation was on hand to hear the exchange.

Mardonius decided to march again to Athens, and the Athenians once again evacuated to Salamis, while the Persians burned Athens for a second time. Mardonius again sent another delegation to Salamis to make an alliance. The Athenians sent a delegation of Sparta to demand that Sparta honor the alliance. The delegation was informed that Sparta was celebrating the festival of Hyacinthus in honor of Hyacinth, a lover of Apollo and a hero. His cult was celebrated in Laconia along with Apollo. The Spartans planned not to fight until another ambassador told them that all of Greece needed the Spartans to unify them and save their homeland. The Spartans held a council that night and decided that since the actual festival was completed, the army could be released. The next day, the Athenian delegation returned with the intent that if their demands were not met, then they would sail away from Greece. They were soon shocked to discover that the entire Spartan army had already left and marched north.

The Greek army was a confederation force, with each unit having its own commander, but all the units were under the command of the Spartan regent and general Pausanias. The Spartans sent 5,000 Spartiates (full citizens) hoplites, 5,000 other Lacedemonian hoplites (presumably perioeci), and 35,000 helots not armed as hoplites but light infantry, for a total of 45,000 Spartans, the largest force ever assembled. In addition, there were probably another 25,000 Greek hoplites, for a total of about 35,000 hoplites in the Greek army and 30,000 to 35,000 lightly armed troops from the other Greek cities.

These combined forces, 35,000 hoplites and 60,000 to 70,000 lightly armed troops, skirmishers, and archers, allowed a force of 100,000 Greeks to have assembled. Although the lightly armed troops would not have been crucial to the actual battle, they were needed to prevent the Persians from outflanking the hoplite force with their cavalry, and if the army needed to retreat from the battle, they would be used to cover their evacuation. In addition, it is possible that the number of heavy troops was reduced further since the fleet in Asia Minor with 110 triremes would need about 22,000 troops. Nevertheless, the Greek army must have been exceedingly large for that period, and a force of some 60,000 to 100,000 total, with 35,000 hoplites, is not impossible.

Meanwhile, the Persian force, not likely to be at the 300,000 recorded by Herodotus, probably sent about 100,000 men, with the remaining 100,000 spread out over Thessaly and Macedon. Half of the Persian force would be composed of Persians (said to be 40,000), with another 20,000 from the east (Bactrians, Indians, Sakae) and an equal number from Greek allies, perhaps half of which were hoplites, especially the Thebans, as well as about 5,000 Persian cavalry.

The Persians did not need to risk fighting. The Greek alliance had nearly come apart in the winter due to competing Greek interests. If Mardonius had waited, he probably would have seen the end of the alliance. Nevertheless, he could not allow the Greek army to attack Thebes, and he needed to be sure that his newly acquired allies remained faithful. He had better supplies, and if he wanted, he could secure northern Greece while waiting for southern Greece to fall apart. The Greeks needed to force a battle on grounds favorable to them, which would negate the Persian cavalry, which could outflank them. In addition, it was crucial to knock the Persians out of the war to make sure that they left Greece.

Mardonius now retreated from a destroyed Athens and made Thebes his base as he waited for the Spartan army to advance. His plan was to use the open country of Boeotia to the advantage of his cavalry and defeat the Greeks once and for all. His fortified camp was just north of Plataea, on the banks of the Asopus River.

It is said that the Athenians, who sent 8,000 hoplites and 600 remnants of Plataea, marched toward Thebes and were soon awed to see the entire Spartan army on the plains of Plataea. The Spartan army was led by the regent Pausanias, who deployed the allied army on the high ground overlooking the Persians and avoiding ground favorable to the cavalry.

Mardonius tried several strategies and attempts to get the Greeks to attack. His cavalry initiated hit-and-run skirmishes to engage outliers and advance guards. The attacks showed some success until the Persian leader of the cavalry was killed and the Persians retreated. The allied army was spread out over several hills, with the Spartans on the right, the Athenians on the far left, and other allies in between. Mardonius moved out of his camp and advanced to the Asopus River, where both sides remained stationary for eight days.

The Persians used their cavalry to raid the Greek supply lines further, sowing dissension and threatening their continual deployment. After two more days, the Persian cavalry took over the springs supplying the Greeks with fresh water, further hampering their army. Pausanias decided to move the army back to where Plataea could defend their flanks and the Greeks could be provisioned with food and water. One Spartan unit refused to move, which caused disunity in the Spartan part of the ranks. During the night, the plan was implemented, but due to darkness, the central line did not arrive at their appointed positions but instead were spread over the Plataean plain. By morning, the entire Greek army line was in disarray, with units scattered and no cohesive lines formed. At this point, the Persian camp awoke.

The armies were arranged based on their hoplite strength, according to Herodotus, with the Spartans at 10,000 on the right side facing the Persians. Next to the Spartans were mainly the Corinthians and Sicyon, numbering about 10,000, who fronted the Medes. Other members of the Peloponnesian League faced the Bactri- ans, with about 2,500 hoplites. The men from Euboea and nearby towns numbered about 1,500 heavy infantry facing the Indians. Troops from western Greece came next, with 1,500 hoplites facing the Sacae. The Athenians and Plataeans, numbering about 9,000 heavy forces, fronted the Persian Greek allies, specifically the Thebans, Thessalians, and Macedonians, who seemingly would have been armed as hoplites. There were also Persian troops from inner Asia Minor, Egypt, and Ethiopia.

When the Persians saw the Greek forces in disarray, Mardonius probably believed that the Greek alliance had broken up and their army was in full retreat. It was this situation, rather than any particular desire of Mardonius to engage in battle, that forced the end of the stalemate; Mardonius probably thought that he could rout the retreating Greeks and wipe them out. As for the Greeks, they were still on higher ground, which negated the Persian cavalry’s strength and allowed them to be fooled into attacking. Mardonius now crossed the river and advanced with his Persian infantry, followed by the rest of his army. The Persian cavalry dislodged a Spartan company from the ridge, and the Athenians, battling the Thebans, could not join up with the main Spartan force.

With the cavalry attacking the Spartan main forces, Mardonius and his infantry arrived and began to fire arrows. The Spartans still did not attack until units from Tegea began to attack. Pausanias, now receiving favorable omens, ordered the Spartans to advance. As at Marathon, the Persian army’s heaviest infantry was inferior to the Greek hoplites. The Spartans and Tegeans continued their advance, and Mardonius, with 1,000 bodyguards, continued to order the attack. During the battle, Mardonius was killed and the Persians began to waver and then fled.

The Persian general Artabazus, who did not counsel fighting and had not committed his troops, soon saw the flight of the main Persian army and ordered his men to retreat toward Thessaly in the hope of saving his force. He ultimately reached Asia Minor but lost many men in Thrace and Macedon. The Spartans were successful on the right wing, and the Athenians had finally beaten back the Thebans on the left side. The Greeks then attacked the Persian camp and massacred most of the remnants. It is said that the Greeks wanted to mutilate the body of Mardonius, but Pausanias refused, as he felt that it would bring dishonor and vengeance from the gods.

Supposedly on the same day, the Greeks won a great naval battle at Mycale in Asia Minor. With these twin victories, the Persian offensive against Greece ended. Although many wanted to punish Thebes by destroying it, Sparta realized that it would be needed to counter Athens in the future.