The collapse of Athenian power in the Peloponnesian War (431-404 BCE), the weakening of the Spartans by their oliganthropia (demographic decline), and the inconclusive Corinthian War (395-386 BCE) has paved the way externally for Theban ascendancy.

Sparta's involvement in Persian civil wars in Asia Minor under Agesilaus II (ruled 399-360) and the subsequent Spartan occupation (382) of the Theban citadel, Cadmea, overextends Spartan power.

The Boeotian or Theban War, which breaks out in 378 BCE as the result of a revolt in Thebes against Sparta, lasts six years.

A peace treaty is agreed but things go seriously awry at the signing—Epaminondas insists that he should sign for the Boeotians as a whole rather than just Thebes, at which the Spartan king Agesilaus strikes the name of Thebes off the list of signatories.

Most of Greece implements the treaty, which means that Thebes faces the Spartan expedition against her alone.

However, the resulting battle at Leuktra in 371 BCE is a decisive Spartan defeat and ushers in the era of Theban hegemony.

Epaminondas goes on to liberate Messenia from Spartan control.

Amyntas III of Macedon seeks Spartan aid against the growing threat of Olynthus, seat of the Chalcidian League, and the Spartans eagerly respond.

That Olynthus is backed by Athens and Thebes, rivals to Sparta for the control of Greece, provides them with an additional incentive to break up this growing power in the north.

Amyntas thus concludes a treaty with the Spartans, who assist him in reducing Olynthus (379).

He also enters into a league with Jason of Pherae, and assiduously cultivates the friendship of Athens.

Aat a Panhellenic congress of the Lacedaemonian allies in 371 BCE, he votes in support of the Athenians' claim and joins other Greeks in voting to help Athens to recover possession of Amphipolis.

With Olynthus defeated, Amyntas is now able to conclude a treaty with Athens and keep the timber revenues for himself.

Amyntas ships the timber to the house of the Athenian Timotheus, in the Piraeus.

By his wife, Eurydice, he has three sons: Alexander II, Perdiccas III and the youngest of whom is the famous Philip II of Macedon.

Amyntas dies at an advanced age, leaving his throne to his eldest son, Alexander, who is very young in 371 when he ascends to the throne.

This causes immediate problems for the new king as enemies to the dynasty resume war.

Alexander is simultaneously faced with an Illyrian invasion from the northwest and an attack from the east by the pretender Pausanias.

Pausanias quickly captures several cities and threatens the queen mother, who is at the palace in Pella with her young sons.

Alexander defeats his enemies with the help of the Athenian general Iphicrates, who had been sailing along the Macedonian coast on the way to recapture Amphipolis.

Thásos, which had again allied to Athens in 389 BCE, becomes a permanent member of the Second Athenian League.

Timotheus, the son of the celebrated general Conon, is elected strategos in 378 BCE and wins over the Acarnanians and Molossians as friends of Athens.

Argive loyalty to Corinth had soon wavered after the federal unification of 392, and, after Thebes revolts against Sparta in 379, democrats take power in Argos.

Pelopidas had been elected boeotarch, or chief magistrate, of Thebes in 379 BCE (and will be in subsequent years).

After Thebes allies defensively with the Athenians, the Boeotian league is reconstituted on an initially successful democratic basis: all Boeotians, whatever their property, are members of an assembly convened at Thebes; their vote decides all matters of policy.

The seven-man executive (one from each of the then seven districts, of which Thebes controls three) is directly responsible to the Assembly.

Agesilaus reduces Thebes to near starvation in two sieges in the years 378 and 377 BCE.

The charter of the new Athenian confederacy is issued at the beginning of 377.

Athens is right to suspect Spartan anger; an attempted raid on the Piraeus by the Spartan Sphodrias at this time, best seen as a response to the new mood in Athens, fails in its object, whatever exactly this is.

Once again, Sparta does not pursue the offender.

The “charter” document, which sets out the aims of the new confederacy, singles out Sparta as the enemy, while the main ally is Thebes.

Hostility toward Sparta, however, though it is certainly the motive shared by Athens and Thebes, does not adequately explain the participation of islanders such as …

…the Rhodians and …

…the Chians.

The main fear in these islands must be of encroachment by such Persian satraps as the energetic Hecatomnids of Caria.