Isocrates hails the Sicilian tyrant Dionysius as…

The Boeotian League opposes Sparta in the Corinthian War (395-387) and is defeated and again dissolved, Sparta having had Persian help.

However, Thebes, …

…Thessaly, and …

…a resurgent Athens each is able to carve out small domains for themselves because of Spartan ineptitude.

Sparta compels the cities of Acarnania, a region of west-central Greece, to give up the Athenian alliance in 388 BCE.

Plato travels in about 388 BCE to Italy and Sicily, where he forms a friendship with Dionysius of Syracuse and his brother-in-law Dion.

Pythias of Syracuse, implicated in a plot against the tyrant, is sentenced to death.

Before the execution, he receives permission from Dionysius to set his affairs in order, on the condition that his best friend Damon take his place as a pledge against his return.

Pythias is delayed and returns only moments before the execution of Damon is to take place.

This display of devotion so impresses Dionysius that he pardons Pythias. (The two comrades, celebrated for their loyalty to each other, will come to symbolize friendship.)

Ephesus had shared in a general revolt of 412 BCE against Athens, siding with Sparta in the Second Peloponnesian War, and had remained an effective ally of Sparta down to the end of the war.

Threatened by Persia after 403, Ephesus had served in 396 as the headquarters of King Agesilaus of Sparta.

The Ephesians in 394 had deserted to Conon’s anti-Spartan maritime league, but by 387 the city is again in Spartan hands and is handed by Antalcidas to Persia, inaugurating the pro-Persian tyranny of Syrphax and his family.

Artaxerxes secures the King's Peace (also called the Peace of Antalcidas) in 387, which asserts Persia's ancestral claim to Ionia and specifies that Asia, including Clazomenae, is included because Athens had interfered there and because its status—whether it is an island or part of the mainland—is unclear. (It is in fact a peninsular site.)

Erythrae, following a period of party strife, becomes subject to Achaemenidian Persia in 387 BCE.

All of Caria is rejoined under the King's Peace to Persia's Achaemenian Empire as a separate satrapy under the rule of the native Hecatomnid dynasty.

Plato, upon his return from Syracuse to Athens in 387 BCE, establishes the innovative Academy, an institution devoted to research and instruction in philosophy and the sciences.

He plans to have a single center for teaching and research that will draw together experts in all branches of learning and that will include younger scholars to give continuity to its work.

According to tradition, Akademus, a local hero of the Trojan War, had owned the garden long ago.

His former garden, or olive grove, was therefore called “akademia” before Plato established his Academy there.

In addition to Plato, the mathematician Eudoxus of Cnidus is a senior member of the faculty.

Plato emphasizes geometry in and uses the five regular polyhedrons to explain the scientific phenomena of the universe.

The Academy, where scholars conduct rigorous research with their students, may be considered among the first universities.