Achaemenid prince Cyrus the Younger had been…

The orator Lysias delivers his most important speech, “Against Eratosthenes,” written in 403 in prosecution of the man who had caused the execution of his brother. (Lysias’s most successful speeches, however, are those he writes for clients to deliver in the Athenian law courts. His speeches, of which thirty-four survive, will become the model of the "plain style" in the eyes of later students of rhetoric.)

Under the archon Euclides, Athens officially adopts the Ionian alphabet in 403 BCE. (Each Greek state has its own alphabet, but use the Ionian alphabet for capital letters. The standardized alphabet soon spreads throughout Greece.)

A small army of democrats under Thrasybulus marches south from Phyle to depose the reactionary Thirty and restore democratic rule, and Critias is killed in fighting in the Piraeus.

Lysander, sent to support the Thirty at Athens against Thrasybulus' democratic revolt, is nearly successful, but a reversal of policy in Sparta leads by the end of 403 to a settlement that allows the restoration of democracy at Athens.

(One of the Spartan kings, Pausanias, is instrumental in this, though he narrowly escapes condemnation at a trial held in Sparta.)

This is a defeat for Lysander; his decarchies probably are abolished and, most likely, he suffers a political eclipse.

Lysander seizes the wealthy island of Thásos in 403 BCE.

The Samians have alternately supported Persia and Athens over the past century, but after the defeat of Athens in the Peloponnesian War, Spartan hegemony replaces the Athenian.

Lysander, initially regarded as the savior of the non-Athenian Greeks, wins their enmity and that of the Spartan authorities by arbitrarily arranging the governments of the cities that he had liberated from Athens.

Many of Athens' former allies come to be ruled by “decarchies,” or juntas of ten, composed of his partisans, often reinforced with garrisons under a Spartan commander (harmost), as, for example, on Samos.

Dionysius destroys Naxos in 403 BCE, expelling or enslaving its Greek population and giving its territory to the Sicels.

Dionysius’ position at home is threatened in 403 BCE by those philosophically opposed to tyranny.

Sparta, which has in the past deposed tyrants from Corinth to Athens, does not damn Dionysius and his autocracy.

Relations between the two are in fact very positive; Dionysius even has the privilege of being allowed to conscript mercenaries from lands under Spartan authority.

The demise of a prominent democratic polis in the classical world and the subsequent tenure of Dionysius represents what is to become a recurring norm in fourth century Greece, thanks to the prevalence of mercenaries.

Cyrus, upon reaching the Euphrates River at Thapsacus, announces that he is marching against Artaxerxes.

The mercenaries demur on discovering that the Persian throne is the true goal, but Cyrus's offer of double wages rekindles their interest, and the expedition marches east.

Cyrus advances unopposed into Babylonia, but Artaxerxes, warned at the last moment by Tissaphernes, is hastily gathering an army.

The decisive battle is fought at Cunaxa, on the left bank of the Euphrates River north of Babylon, where the two armies meet unexpectedly on September 3.

Cyrus's Greek mercenaries seem initially to have won the battle, routing the Persian left with few casualties, while Cyrus himself charges Artaxerxes' center with six hundred cavalry.

However, Cyrus loses his life in trying personally to kill his brother, whom he only wounds, at which point the mercenary army falls apart.

The Greeks fight on fiercely through the day, but eventually surrender the fighting ground and begin a retreat. (The Athenian mercenary Xenophon will accord Cyrus high praise in the “Anabasis,” his lively firsthand account of the retreat of the Ten Thousand).

The Greeks return to find that the rest of Cyrus' troops have been routed and his camp plundered.

The Persians, during truce negotiations with Tissaphernes, who has supported Artaxerxes and distinguished himself in the battle, treacherously seize Clearchus and other Greek leaders, then turn them over to Artaxerxes, who executes them.

The defeated remnants of the Ten Thousand, trailed by Persian troops, make a desperate thousand-mile retreat from Babylonia through the heart of hostile territory toward the nearest friendly haven, the Greek colony of Trapezus on the Black Sea coast.

The Greeks, led by Xenophon and others during the five-month march, live off the land, repel attacks from barbaric hill tribes, and suffer through a harsh winter.

Clearchus of Sparta, who takes refuge with Cyrus the Younger in 403 after his expulsion from Byzantium, recruits the Greek mercenary army called the Ten Thousand in support of Cyrus’s claim to the Persian throne.

The ostensible reason for the invasion is a punitive expedition against Persia.

Comprising about twenty thousand men, including nearly thirteen thousand Greek mercenaries, the expedition marches east in the spring of 401.

Around six thousand survivors make it to Trapezus, and take ship to …