The Battle of Abydos was an Athenian naval victory in the Peloponnesian War. In the battle, the Spartan fleet, under Mindarus, attempted to rescue a small allied fleet that had been driven ashore at Dardanus, but was attacked by the Athenian fleet, under Thrasybulus. The fighting was evenly contested for a great length of time, but towards evening, the arrival of Alcibiades with Athenian reinforcements tipped the balance in favor of the Athenians, and the Peloponnesians were forced to flee back to their base at Abydos, suffering heavy losses along the way. Prelude After the Athenian victory at Cynossema, the Athenian fleet established a base at Sestos, from where it could quickly respond to any moves by the Spartan fleet at Abydos. 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. Dorieus, accordingly, sailed north from Rhodes towards the Hellespont. Before reaching Abydos, however, he was spotted by Athenian lookouts and driven ashore. Xenophon reports that he was trapped at Rhoeteum, while Diodorus Siculus reports the location as Dardanus; Donald Kagan suggests that Dorieus was driven ashore at Rhoeteum, then managed to advance a little farther towards Abydos before being trapped a second time at Dardanus. Learning of Dorieus's plight, Mindarus hurried from Troy, where he had been sacrificing to Athena, to Abydos, while Pharnabazus brought his army up to support Dorieus from the land. Mindarus led his ships out from Abydos to rescue Dorieus; the Athenians, observing this, set out from Sestos to challenge him. Battle Mindarus, after joining forces with Dorieus, had 97 ships under his command; the Athenian fleet contained 74 ships. The Spartans lined up for battle with the Asian shore of the Hellespont at their backs, with Mindarus commanding the right and the Syracusans holding the left; the Athenians lined up opposite them, with Thrasybulus commanding the right and Thrasyllus the left. The battle began with a signal from the commanders, which was relayed to the fleet by trumpeters. 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. As the day wore on, neither side was able to gain a decisive advantage until Alcibiades appeared with 18 triremes from Samos. Initially, both fleets believed