Mindarus, the Spartan navarch, summoned the Rhodian commander Dorieus, with his 14 ships, to join him at Abydos, hoping to end the war with a decisive victory.
An evenly matched fight ensued, with pilots attempting to ram and disable enemy triremes, while marines on the decks engaged their opposite numbers whenever they came within range of an opposing ship.
Initially, both fleets believed that the reinforcements might be theirs, but as Alcibiades drew nearer he ran up a red flag, a prearranged signal that told the Athenians the ships were their own.
Alcibiades, who had served as Tissaphernes' assistant for a time and wished to demonstrate that he was influential with the satrap, sailed to meet him, bringing gifts.
The Spartans had complained to the Persian king about the tepid support they had received from Tissaphernes, and the satrap, needing to demonstrate his commitment to opposing actions, arrested Alcibiades and imprisoned him at Sardis.