Pagondas moved his army into position near the Athenians although both armies were hidden from each other by a hill. The Boeotians had 7,000
hoplites, 1,000
cavalry, 500
peltasts and 10,000 light troops. The right wing was formed by troops from Thebes, and the Thebans drew themselves up to a depth of 25 men, rather than the usual 8; the centre by men from
Haliartus,
Coronea, and
Copiae; and the left wing by troops from
Thespiae,
Tanagra, and
Orchomenus. They were later joined by the
Locrians. When Hippocrates learned of the Boeotian army, he joined the main Athenian force, leaving 300 cavalry behind at Delium. The Athenians had about the same numbers of hoplites and cavalry, but had fewer lightly armed troops, mostly from their allied cities. They lined up at the usual depth. Because of the asymmetry in deployment, the Theban right wing would almost certainly be victorious but also because of their deployment the Athenian hoplite line was longer and would outflank the Boeotian left line. That unique deployment by the Theban general Pagondas explains the subsequent unfolding and progress of the battle. The Boeotians charged unexpectedly while Hippocrates was giving a speech to his men. The centre lines saw the heaviest fighting. As
Thucydides reports, the Boeotian left wing was surrounded and close to defeat, and only the Thespian contingent stood its ground. The victorious Athenian line got into confusion as it circled round the Thespian contingent and surrounded it. Some of the Athenian hoplites fought and killed one another when they met at the other end, mistaking their countrymen for the enemy. That was history's first documented incident of "
friendly fire". It is thought the incident occurred in part because no "state" shield devices were in use, which did not seem to have become general until the
Second Battle of Mantinea, fought in 362 BC between the Thebans and the
Spartans (and each side's allies) . In any case, Pagondas sent his cavalry to support the Boeotian left wing and the Athenians were defeated in turn. Meanwhile, the Boeotian right wing was also victorious, and the Athenians fighting there fled. When the Athenian centre saw that its two wings had been defeated, it also fled. About 500 Boeotians and 1,000 Athenians had been killed, including Hippocrates. One of the Athenian hoplites in the battle was the philosopher
Socrates.
Plato has
Alcibiades give the following account of the retreat of the Athenians at Delium, and Socrates' own actions then: The Boeotians chased the Athenians until nightfall. Most of the Athenians returned to the fort at Delium, where a Boeotian herald announced that they were offending land that was sacred to the Boeotians and must leave. The Athenians replied that the land was now theirs and was now sacred to them and that they held it in self-defense from the Boeotians. ==Aftermath==