Battle of Leuctra
When war broke out afresh with Thebes, Agesilaus twice invaded Boeotia (in 378 and 377 BC), although he spent the next five years largely out of action due to an unspecified but apparently grave illness. In the congress of 371 an altercation is recorded between him and the Theban general Epaminondas, and due to his influence, Thebes was peremptorily excluded from the peace, and orders given for Agesilaus's royal colleague Cleombrotus to march against Thebes in 371. Cleombrotus was defeated and killed at the Battle of Leuctra and the Spartan supremacy overthrown.