Battle of Sybota The Battle of Sybota took place in 433 BC between Corcyra ( modern Corfu ) and Corinth , and was , according to Thucydides , the largest naval battle between Greek city states until that time . It was one of the immediate catalysts for the Peloponnesian War . Corinth had been in dispute with Corcyra , an old Corinthian colony which no longer wanted to remain under Corinthian influence . Corcyra , which had the second largest navy in Greece at the time , allied with Athens , an enemy of Corinth ( Corinth was allied with Sparta ) . Athens sent ten ships to Corcyra to reinforce the Corcyraean fleet , with instructions not to fight the Corinthian fleet unless they attempted to land on the island . Corinth , meanwhile , assembled a fleet of ships under the command of Xenoclides and prepared to sail to Corcyra . Corcyra gathered a fleet under Miciades , Aisimides , and Eurybatus , who made the Sybota islands their base of operations . The Athenian commanders , Lacedaimonius ( the son of Cimon ) , Diotimus , and Proteas , sailed with them . Corcyra had 110 ships , plus an additional 30 provided from ally Athens , while Corinth had 150 ships . When the Corinthian ships arrived , the Corcyraeans formed their line of battle , with the Athenians on the right and their own ships making up the rest of the line in three squadrons . The Corinthian ships were lined up with the Megara ns and Ambraciots on the right , the Corinthians on the left , and the remainder of their allies in the centre . Both sides fought with hoplite s on their ships , along with archers and javelin - throwers , in a manner Thucydides calls " old - fashioned . " Instead of ramming and sinking the other ships , both sides attempted to board their opponents ' ships and fight what was essentially a land battle at sea . The Athenian ships , although they were part of the line , did not at first join the battle , as the Corinthians had not attempted to land . The Corcyraean ships on the left routed the Corinthian right wing , chasing them all the way back to their camp on the coast , which they then burned . The Corinthian left wing , however , was more successful , and the Athenians were forced to come to the aid of their allies . Nevertheless , the Corinthians were victorious , and sailed through the wreckage of defeated ships often killing survivors rather than taking prisoners ( including , although they did not know it , some of their own allies who had been defeated on the right - wing ) . They did not kill everyone , however , and captured a number of prisoners . The Corycraeans and Athenians headed back to Corcyra to defend the island , but when the Corinthians arrived , they almost immediately retreated , as more Athenian ships under the command of Glaucon were on their way . The next day , the new Athenian ships threatened a second battle if the Corinthians attempted to land on Corcyra . The Corinthians retreated completely rather than risk another battle . Both the Corinthians and Corcyraeans claimed victory , the Corinthians having won the first battle , and the Corcyraeans having avoided a Corinthian occupation of their island . Soon after this battle , the Athenians and Corinthians fought again at the Battle of Potidaea , leading to a formal declaration of war from Sparta .