Battle of Abydos 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 Syracusan 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 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 . Realizing this , the Spartan fleet fled to Abydos , but suffered heavy losses along the way , as the Athenians attacked the strung out ships . All told , the Athenians captured 30 Spartan ships and recovered the 15 of their own that the Spartans had taken at the Battle of Cynossema . Aftermath . In the wake of this serious defeat , Mindarus and the Spartan fleet returned to Abydos to repair and rebuild ; Mindarus sent to Sparta for reinforcements and , with Pharnabazus , planned for future campaigns . The Athenians , meanwhile , were unable to press the advantage they had gained . With their treasury low and a crisis ongoing at Euboea , which was in revolt , the Athenians were unable to keep their entire fleet in the Hellespont , and instead dispatched 30 ships under Theramenes to attack the rebels on Euboea . Although unable to prevent the rebels from building a causeway to Boeotia , he did succeed in raising a substantial amount of money by plundering hostile territory in Euboea , Boeotia , and the Aegean . Shortly after the battle , the satrap Tissaphernes arrived from Ionia . 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 . It turned out , however , that Alcibiades had misjudged the situation . 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 . Alcibiades escaped within a month , but his claims of influence with Tissaphernes were destroyed .