The battle of Leuctra, where Epaminondas drew his phalanx obliquely to the left to split the Spartan right wing (Plutarch's Parallel Lives Plut. Pelopidas 23)
Athenian and Theban envoys negotiate peace at Sparta. The generals withdraw from each other, and they swear an oath on the condition that the cities be independent. (Xenophon, Hellenica 6.3.2–6.3.19)
Thebes proposes writing 'Boeotians' instead of 'Thebans' in the treaty they had signed in the morning, but this is refused and Thebes is excluded from the peace. (Xenophon, Hellenica 6.3.19)
Cleombrotus camps at Leuctra, and Thebes encamps on the hill opposite. (Xenophon, Hellenica 6.4.4)
Battle of Leuctra: the Theban cavalry first breaks the Lacedaemonian cavalry, and the phalanx fifty shields deep charges; Cleombrotus and about four hundred Spartans fall, nearly a thousand dead in all. (Xenophon, Hellenica 6.4.12–6.4.15)
On the last day of the Gymnopaedia, news of the defeat at Leuctra reaches Sparta; the ephors, though grieving, do not stop the chorus. (Xenophon, Hellenica 6.4.16)
Thebes asks Athens for reinforcements, but the Athenian council is cold. Jason, pretending to prepare triremes, goes overland to Boeotia. (Xenophon, Hellenica 6.4.20–6.4.21)