The immediate outcome of Cynoscephalae is favorable for Thebes and Thessaly is reorganized in a way that gives Thebes for the first time an absolute majority of votes on the Delphic Amphictyony, but active Theban interference in Thessaly is over.

Epaminondas in 364-363 BCE makes a bold attempt in 364-363 BCE to challenge Athens' naval empire.

Some naval interest on the part of Thebes can perhaps already be inferred from its designs on Thessaly, with its good harbors.

Theban rivalry with Athens had become explicit  after 365 BCE, however; Thebes plans a fleet of one hundred triremes, …

…lures away Athenian allies such as Rhodes and Byzantium, and …

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.

Perdiccas tries to reconquer upper Macedonia from the Illyrian Bardylis in 360 BCE, but the expedition ends in disaster, with the king killed in a catastrophic battle.

Philip, originally appointed regent for his infant nephew Amyntas IV, the son of Perdiccas, soon manages to take the kingdom for himself, ascending the throne in 359 as Philip II.

The Illyrians continue to raid from the northwest, the Paeonians from the north, and foreign powers continues to support two claimants to the throne other than Philip, a man of exceptional energy, diplomatic skill, and ruthlessness.

Philip's military skills and expansionist vision of Macedonian greatness bring him early success.

He first has to reestablish a situation which had been greatly worsened by the defeat against the Illyrians, Macedon's permanent enemies.

The Illyrians prepare to close in; the Paeonians, forced northward by the growth of Macedon, are raiding from the north, the Thracians have sacked and invaded the eastern regions of the country, while the Athenians have landed at Methoni on the coast, a contingent under a Macedonian pretender called Argeus.

Using diplomacy, Philip pushes back the Paeonians and Thracians promising tributes, and crushes the three thousand Athenian hoplites.

Bardyllis is killed in battle after Philip rejects his offer of peace based on retaining conquered lands.

Momentarily free from his opponents, Philip concentrates on strengthening his internal position and, above all, his army, introducing more rigorous training and employing mercenaries.

His most important innovation is doubtless the introduction of the phalanx infantry corps, armed with the famous sarissa, an exceedingly long spear, at this time the most important army corps in Macedonia.

This enables him to inflict defeats on the Illyrians and other northern enemies such as Paeonia, which he invades in 358.

The murder of Alexander of Pherae is assigned to 357/356 BCE by Diodorus.

Plutarch gives a detailed account of it, with a lively picture of the palace.

Guards watched throughout the night, except at Alexander's bedchamber, which was at the top of a ladder with a ferocious chained dog guarding the door.

Thebe, Alexander's wife and cousin (or half-sister, as the daughter of Jason of Pherae), concealed her three brothers in the house during the day, had the dog removed when Alexander had gone to rest, and, having covered the steps of the ladder with wool, brought up the young men to her husband's chamber.

Though she had taken away Alexander's sword, they feared to set about the deed until she threatened to wake him.

Her brothers then entered and killed Alexander.

His body was cast into the streets, and exposed to every indignity.

Of Thebe's motive for the murder, different accounts are given.

Plutarch states it to have been fear of her husband, together with hatred of his cruel and brutal character, and ascribes these feelings principally to the representations of Pelopidas, when she visited him in his prison.

In Cicero the deed is ascribed to jealousy.

Other accounts have it that Alexander had taken Thebe's youngest brother as his eromenos and tied him up.

Exasperated by his wife's pleas to release the youth, he murdered the boy, which drove her to revenge.