In the meantime the Isthmian games took place, and the Athenians, who had been also invited, went to attend them, and now seeing more clearly into the designs of the Chians, as soon as they returned to Athens took measures to prevent the fleet putting out from Cenchreae without their knowledge.

After the festival the Peloponnesians set sail with twenty-one ships for Chios, under the command of Alcamenes. The Athenians first sailed against them with an equal number, drawing off towards the open sea. The enemy, however, turning back before he had followed them far, the Athenians returned also, not trusting the seven Chian ships which formed part of their number,

and afterwards manned thirty-seven vessels in all and chased him on his passage along shore into Spiraeum, a desert Corinthian port on the edge of the Epidaurian frontier. After losing one ship out at sea, the Peloponnesians got the rest together and brought them to anchor.

The Athenians now attacked not only from the sea with their fleet, but also disembarked upon the coast; and melee ensued of the most confused and violent kind, in which the Athenians disabled most of the enemy's vessels and killed Alcamenes their commander, losing also a few of their own men.