Ictinus, who, together with Callikrates has designed the Parthenon, takes time off in 440 to work in Eleusis on the ongoing construction of the Telesterion, or Hall of Mysteries, a colossal hall for religious rites with a central light source in the roof.

Samos, one of Athens' principal allies with a substantial fleet of its own, revolts in 440 against Athenian control.

Corinth, in a congress of the Peloponnesian League, votes against intervention against Athens on behalf of Samos. (Corinth's attitude has no doubt softened with the detachment of Megara from Athens.)

Sparta, however, seems to want to stop Athens in its tracks, though, in the end, it is typically unwilling to press this line of policy home. (At this point Thucydides' main narrative stops for five crucial years, at the end of which tension between Corinth and Athens will again be high, on the eve of the great Peloponnesian War.)

Sophocles serves jointly with Pericles as general during the Samian revolt. (According to tradition, Sophocles owes his election to the success of Antigone the previous year.)

Despite a victory by Pericles against superior numbers, the revolt nearly succeeds.

The campaign to recover Samos is long and costly—a four-figure sum in talents—but ultimately successful, and it will become a model against which later Athenian generals measure their achievements.

Mytilene, the port of Lesbos, is built on an island and later connected to Lesbos by causeway, forming the two harbors.

Lesbos takes its name “Pentapolis” from the five cities of Mytilene, Methymna, Antissa, Eresus, and Pyrrha. (Another important city is Arisba, northwest of Kalloní, which is destroyed by an earthquake in Herodotus' time.)

Athens' recent savage reduction of Samos, a member of the Delian League, does not stop Mytilene and most of Lesbos from appealing at some time in the prewar period to Sparta for encouragement in a revolt they are meditating.

No encouragement is given: Sparta is standing by the Thirty Years' Peace, at least for the time being.

Phormio, one of the generals who had led reinforcements to the Athenian siege of Samos in 440, assists the Acarnanians and Amphilochians against Ambracia around the same time.

This results in an alliance with Acarnania, a place close to areas of traditional Corinthian influence.

Legend has Spurius Maelius, a wealthy plebeian, buying up a large supply of grain and selling it at low prices to the Roman people during the severe famine of 440—439.

Lucius Minucius Augurinus, the patrician praefectus annonae (president of the market), thereupon accuses him of courting popularity with a view to making himself king; the cry is taken up.

Maelius, summoned in 439 before the aged Cincinnatus, specially appointed dictator to resolve the situation, refuses to appear, and is slain by magister equitum Gaius Servilius Ahala; his house is razed to the ground, his wheat distributed among the people, and his property confiscated.

The open space called Aequimaelium, on which his house had stood, preserves the memory of his death.

Cicero calls Ahala's deed a glorious one, but, whether Maelius entertained any ambitious projects or not, his summary execution was an act of murder, since by the Valerio-Horatian laws the dictator was bound to allow the right of appeal.

Ahala is brought to trial, and only escapes condemnation by going into voluntary exile.

A bill will be brought forward three years afterwards, in 436 BCE, by another Spurius Maelius, a tribune, for confiscating the property of Ahala, but it fails to pass.

(A related tradition, also discounted by most scholars, has Cincinnatus receiving a second dictatorship to check Maelius’s monarchial ambitions, then once again ceding the reins of power after the crisis ends.)

The Spartocid dynasty replaces that of the Archeanactids in the Bosporan Kingdom in 438 BCE, annexing to Panticapaeum other Greek colonies—e.g., Nymphaeum, which had been founded in the region in the seventh and sixth centuries.

Pericles takes a fleet into the Black Sea at an unknown date, but probably in the early 430s, to demonstrate Athenian power and secure the grain route from the Tauric Chersonese (the Crimean Peninsula in modern Ukraine). (According to another view, this event belongs in the 450s.)