The Battle of Delium was a major battle of the Peloponnesian War which was fought between the armies of Athens and the Boeotian League in Boeotia in November 424 BC.
Led by the general Hippocrates, an Athenian army returning from a foray into Boeotia, northwest of Athens, was caught by an army from that region. The Boeotian general Pagondas drew up his phalanxes on ground hidden by a hill. When the phalanxes came over the hill to attack, the Athenians had to respond swiftly. They charged uphill to meet the enemy, and, in the words of historian Thucydides, the opposing phalanxes, "crashed into one another on the run" and then "stood pushing against each other with their shields in a brutal battle." On the right the Theban phalanx was 25 ranks deep and pressed back the eight-deep Athenian ranks. But on the left the Athenians got the upper hand and butchered many of their enemies when the Boeotian phalanx collapsed. Pagondas ordered his cavalry to attack in support of his weakest wing. Luckily for him, when the horsemen appeared over a hill, the Athenians mistakenly believed a new army was joining the battle. As panic spread, the Athenian force turned and ran back toward the city of Delium, pursued by the Boeotians. Almost 1,000 Athenians were killed, including Hippocrates.