The Boeotian League intervenes also in the Arcadian federation in the Peloponnese, which has split in two; the Tegean party appeals for help to the Thebans (who in turn have for allies the Argives and Messenians), and …

…the Mantineans to Athens and Sparta.

The outbreak of civil war in the Arcadian league in 362 brings Epaminondas once more to the head of a large allied army in the Peloponnese.

Leading the Boeotians and their Argive allies against Sparta, Athens, and their allies in an encounter on the Mantineian Plain, Epaminondas repeats on a large scale the tactics of Leuctra, cleverly outmaneuvering the Spartan troops, and is once more victorious but dies of a wound on the field of battle.

The great Battle of Mantinea (“Second Mantinea,” to distinguish it from the events of 418) is a technical victory for Thebes in the strictly military sense, but (as Xenophon notes) it is actually indecisive: Epaminondas' death permanently crushes Theban hopes of leadership in Greece.

The peace after the battle in effect recognizes the independence of the Messenians, thus settling at the diplomatic level an issue that in reality has been settled for years.

All constructive initiative appears to vanish with the death of Epaminondas from the policy of Thebes, which begins a rapid decline from its decade-long position as Greece's preeminent city-state.

Agesilaus, Eurypontid king of Sparta, had twice rescued Sparta from attacks by the Theban leader Epaminondas but had taken no part in the subsequent Battle of Mantineia.

Agesilaus, commanding a body of Greek mercenaries in 361, is abroad serving Tachos, or Teos (also known as Zedhor), second king of the native Thirtieth Dynasty of Egypt.

Tachos, however, insists on leading the Egyptian army himself, and Agesilaus, after quarreling with his ally, supports a military revolt in Egypt that places the young pretender Nectanebo II on the throne.

A rival pretender almost succeeds in overthrowing the new king, but Agesilaus defeats him and leaves Nectanebo firmly established as ruler. (Tachos flees to the protection of Artaxerxes II in Persia, where he will die an exile.)

The death of Epaminondas in 362 BCE has freed Athens from fear of Thebes, but it appears at the same time to have exposed it to further aggression from Alexander of Pherae, who makes a piratical raid on Tinos and other cities of the Cyclades, plundering them, and enslaving the inhabitants.

Alexander also besieges Peparethus, and "even landed troops in Attica itself, and seized the port of Panormus, a little eastward of Sounion."

The Athenian admiral Leosthenes defeats Alexander and manages to relieve Peparethus, but …

Alexander escapes from being blockaded in Panormus, takes several Attic triremes, and plunders the Piraeus.

Callistratus, impeached again in 361 BCE, escapes to Methone in Macedonia, where he is accommodated by King Perdiccas III, who draws on his financial expertise.

Plato returns to Syracuse in 361 BCE, but his visit with Dionysius proves even more disastrous than the first, and he returns to the Academy the following year.

Xenocrates, a student of Plato’s, may have accompanied him in the latter's political adventures in Sicily.