The Spartans move north from Chios to the Hellespont, gradually overcoming the Athenian navy despite effective countermeasures taken by Alcibiades and others. (This stage of the Peloponnesian war is called "Decelean" from the name of a town in Attica, Decelea, which Sparta fortifies—to the enormous cost of the Athenians.)

The Athenians decisively defeat the combined Persian-Spartan land and sea forces in 410 at the Battle of Cyzicus.

Sparta requests a peace, with the status quo intact, but the demagogue Cleophon, Athens’ new ruler, refuses.

Alcibiades, still officially exiled but appointed commander of the Athenian navy, helps Athens to a spectacular recovery, defeating the Spartan fleet in the Hellespont at Abydos (411 BCE) and Cyzicus (410 BCE) on the shore of the Propontis (Sea of Marmara) and regaining control over the vital grain route from the Black Sea.

Alcibiades installs a garrison at Chrysopolis under Theramenes, who had commanded twenty ships at Cyzicus, to exact a tithe from all shipping that comes from the Black Sea.

This revenue enables the Athenians to put an end to the regime of the Five Thousand and restore their traditional institutions in full.

A commission is set up to codify the law: it is evidently felt that constitutional history had been abused in 411 BCE and that the abuse had been made possible through ignorance.

Codification is to prevent a recurrence; it is expected to take four months (but will still be incomplete after six years).

A fresh start is to be made in 403 BCE.

In a remarkable reversal of the position in 413 BCE when a Spartan victory must have seemed in sight, Sparta (possibly) at this time requests a peace, with the status quo intact, but the demagogue Cleophon, Athens' new ruler, refuses to come to terms. (Xenophon, who now replaces Thucydides as the main source, does not mention the offer.)

Sicily has always been prone to tyranny and political instability, partly because the island is threatened by potentially hostile neighbors ready to encroach and partly because there is a large population of non-Greek indigenous inhabitants such as the Sicel forces mobilized in mid-century by Ducetius.

Polis life has never struck deep enough roots, and populations tend to be mixed and are too often transplanted.

Immediately after the severe defeat of Athens by the Spartans and their allies at Cyzicus.

a radical democracy had been installed in Syracuse, at the instigation of an extremist called Diocles.

The leader of the moderate democrats, Hermocrates, had in held the position of admiral during the battle.

As a result, Hermocrates, who happens to be absent at the time, is banned "in absentia" in 410.

(Hermocrates, who will not return to Sicily until 408 BCE, will die in a street fight after a failed coup in Syracuse in 407 BCE.