The Rules of Naval Warfare in Action: The Battles of Cynosemma, Abydos, and Cyzicus, 411–410

In 411, with the naval war in Ionia not producing the proper results, the Spartans decided on a bold new strategy: a move against Athenian control of the Hellespont. As noted earlier, the Hellespont was literally the lifeline of Athens, as most of the food for its besieged population came down this waterway from the Black Sea. The Athenians already held many of the cities in the Hellespont and had established various lookouts and patrols to deny the Spartans entry. However, the Spartans had managed to establish a base at Abydos, on the southern shore of the Hellespont, by marching an army overland through Anatolia from Miletus; it now had 16 triremes stationed there. For the Spartans, acquiring the base at Abydos was a good start, but as yet they could not seriously threaten Athenian control of the Hellespont. Mindarus, the new navarch (admiral) of the Spartan fleet, was stationed with 73 triremes at Miletus far to the southwest along the coast of Ionia. He wanted to move these ships into the Hellespont to join with those at Abydos. He knew his arrival there would represent such a serious threat to Athenians’ survival that they would be forced to fight a battle in the confined waters of the Hellespont, which would negate their superior speed and tactical ability. If the fighting did not go well, the nearby beaches would also provide places of refuge on which the superior Spartan marines, possibly with help from the nearby Persians, would have an advantage.

The problem was getting his 73 ships past the 75 Athenian triremes stationed at Samos. The Athenian base was well positioned to see the movement of the Spartans, and Mindarus did not want to fight the superior Athenian fleet in the open sea. He devised a ruse: he carefully organized the preparation for the voyage in such a way as to not alert the Athenian lookouts. He then waited until the last possible minute before ordering his men to leave immediately without the overt preparations with which a long voyage usually commenced. Most likely, the move out of Miletus took place at night, since Athenians did not discover the Spartan departure for some time. Apparently, Mindarus intended to head west into the open sea, skirting the western end of the island of Samos rather than going along the coast of Ionia and the eastern end of the island, where there was only a very narrow channel visible to the Athenians. A storm, though, forced him further west, to the island of Icarus, where the fleet was delayed nearly a week. At some point, the Athenians realized that the Spartans had departed and correctly guessed they were making for the Hellespont; they, too, now raced north to bar the Spartans entry. Because of the delay, Mindarus did not make an immediate run to the Hellespont but set off north across the open sea to Chios, an ally of Sparta. The Athenians learned of this and therefore halted their dash toward the Hellespont and instead stopped at Lesbos, directly north of Chios. The Athenians now expected the Spartans to remain at Chios, since their way north was blocked. Unfortunately, during the second part of the war, the Athenians had two missions that often pulled them in different directions and served to divide their forces, something they could ill afford after the disaster in Sicily. The Athenians not only had to fight the new Spartan fleet and keep it out of the Hellespont but also had to prevent revolts by its subjects, which threatened its tribute. Now, in 411, Eresus, one of the subject cities on the southwest coast of Lesbos, revolted. The Athenians posted lookouts on the east coast of Lesbos and on the mainland opposite, believing they would be alerted if the Spartans attempted to sail past. Then, most of the Athenian ships and men moved to crush the revolt. This meant that the main Athenian fleet was out of position when the Spartans moved from Chios. The Spartans received from their allies on Chios supplies and pay for their men; this provisioning took two days. On the third day, far sooner than the Athenians had expected any type of move, they sailed out. Mindarus did not immediately sail north into the open sea as he had before because he wished to avoid the main Athenian fleet at Eresus. Instead, he sailed east, skirting the promontory of Mount Mimas, to the Ionian coast, far to the south of the Athenian lookouts. The sailors disembarked to eat in the neighborhood of Phocaea before spending the rest of the day moving north along the coast. They ate their dinner at the Arginousae Islands, just out of range of the Athenian lookouts, who were directly north along the coast and northwest on Lesbos. They then waited for darkness and sailed between Lesbos and the coast at night, thwarting the efforts of the Athenian lookouts to detect their passing. They halted again to eat at Harmatus, which was just across the straight from Methymna, a city allied to Athens. If it had been light, they surely would have been spotted, but, again through careful planning and a little bit of luck, they arrived at Harmatus before dawn. The next day, they moved quickly north along the coast until, a little before midnight, they came to Rhoeteum, just inside the Hellespont. It had taken a little less than two days to move 73 triremes from Chios to the Hellespont, and the Spartans had been successful in avoiding detection or confrontation with the Athenians trying to block their passage. For the first time in the war, the Spartans had arrived in strength in the Hellespont. They would remain a threat to it for the war’s duration. The nature of the Peloponnesian War and the focus of the naval battle had now switched theaters.

The Athenians stationed at the base at Sestos, on the Hellespont’s northern shore, were alerted to the Spartan’s arrival by the signal fires from the lookouts and by the sudden and dramatic rise in the enemy campfires across the Hellespont on the southern shore. Now massively outnumbered, the 18 Athenian triremes at Sestos then tried to sneak out of Hellespont to rejoin the rest of the fleet. They left by night and so were hidden from the view of the Spartan base at Abydos as they moved along the northern shore of the Hellespont. However, they did not time their run well, for at daybreak they were still in the Hellespont and were spotted by the ships of Mindarus. The Spartans chased the tiny Athenian fleet, and four ships were sunk; the rest got away. The Spartans returned to Abydos, their combined fleet now numbering 86. Meanwhile, the Athenians at Eresus had finally been informed of the Spartans’ success in reaching the Hellespont despite their efforts. Realizing immediately the threat to Athens’ survival, they raced to the Hellespont, picking up the stragglers from Sestos along the way. The Athenians now had 76 triremes.

Both sides were now ready to fight a major naval battle. Mindarus wanted to fight a naval battle in the confined waters in the hope of negating the Athenian advantages in speed and experience. Also, since the battle would be fought close to land, Mindarus hoped to block the Athenians’ escape out to the open sea and instead to drive the Athenians onto shore and there use his superior marines; he could also use the beach or Abydos as a refuge in case the attack did not go well. The Athenians had to fight as well; they could not allow a Spartan fleet to exist in the Hellespont because it would threaten the shipments of grain on which Athens depended.

The battle was fought in October 411 off Point Cynossema. Both lines of triremes stretched from the north to the southwest toward the Hellespont entry. Syracusans manned the Spartan right, while Mindarus held the left. Thrasybulus, one of Athens’ great naval heroes, held the right wing of the Athenian line, while Thrasyllus, who was responsible for allowing the Spartans to sneak past him in the first place, commanded the left. When the battle began, Mindarus headed southwest to block the Athenians, but even in the narrow channel the Athenian ships were still faster, so Thrasybulus was able to avoid the encircling move and instead get around the Spartan left. He immediately turned back to the northwest, hitting the Spartan ships from the sides and from behind. He broke the Spartan left and then continued north to attack the Spartan center, which had pushed the Athenian center back to the beach. However, the Spartan ships had become disorganized during their pursuit of the Athenians, and they were easy prey for Thrasybulus and the Athenian right. The Spartan center scattered as it attempted to make it back to the southern shore or the base at Abydos. When the Syracusans on the right saw their line disintegrating, they too broke and fled, and Thrasyllus and the Athenian left, which had been hard pressed, now went over to the attack. The Athenians won the battle. Diodorus, a Greek historian from Sicily, described the causes of Athenian success:

The pilots of the Athenian fleet, being far superior in experience, contributed greatly to the victory. For although the Peloponnesians had more ships and the valor of their marines, the skill of the Athenian pilots rendered useless the superiority of their opponents. Whenever the Peloponnesians charged forward to ram, the Athenian pilots would maneuver their own ships so skillfully that their opponents were unable to strike them at any spot but could only meet them ram against ram. When Mindarus saw that the force of his rams was ineffective, he gave orders for his ships to come to grips in small groups or one at a time. . . . The Athenians though cleverly avoided the on-coming rams of the ships and struck them on the side and damaged many.

The Athenians set up a trophy, and the dead were collected under truce. The Athenians destroyed 21 enemy ships. Though the numbers were not great, they had avoided defeat in the battle and therefore had avoided defeat in the war. A trireme was sent to Athens with the good news, and after all the recent disasters Athens had suffered, the victory served to revive the Athenian population. According to Thucydides, “the good news . . . greatly heartened the Athenians and they came to believe that if they fought resolutely, final victory was still possible.”


In the immediate aftermath of Cynossema, the Spartans were still in the Hellespont with a substantial fleet, significant bases, and Persian support. Both sides now called for reinforcements from home and from their allies and subjects. Triremes raced to the Hellespont from all over the Greek world. Both sides still desired battle for the same reasons as at Cynossema. In November of 411, a second major battle was fought at Abydos. Fourteen Spartan ships attempted to sneak into the Hellespont to join up with their comrades at Abydos. They were spotted by the Athenian lookouts, who warned the Athenian commanders at Sestos. The Athenian fleet sailed out to attack, while Mindaurs and the Spartans at Abydos raced in to protect their comrades. A tense battle ensued that lasted much of the day until 18 new ships appeared from the west heading toward the battle. The 18 ships were Athenian vessels commanded by Alcibiades; when he came into sight of the battle, he hoisted a red flag to alert his comrades that he was indeed Athenian. His sudden appearance at Abydos turned the battle in favor of the Athenians. The Spartans fled back to Abydos after losing 30 ships.

During the winter of 411–410, both sides prepared for the coming campaign season; the Spartans at Abydos, with Persian money, spent time repairing their ships and building new ones, while the Athenian commanders in the Hellespont Thrasybulus and Theramenes spent their time in the northern Aegean collecting money either through tribute or by plundering. In 410, both sides were again willing to give battle. The Spartans moved first, capturing Cyzicus with the help of the Persians. The Spartans now had a base further east in the Hellespont; Mindarus and 80 triremes were stationed there. The Athenians, again recognizing a threat to their very survival, devised a complicated strategy. Their fleet would be led by their most successful admirals of the war: Thrasybulus, Theramenes, and Alcibiades. They moved toward Cyzicus in heavy rain to conceal their approach, then divided up their forces: Alcibiades took 40 triremes and headed straight for Cyzicus, while Thrasybulus and Theramenes remained hidden to the north of the city. When Mindarus saw only 40 ships approaching, he believed he had a great numerical advantage, so he led out his 80 ships. Alcibiades and his ships pretended to flee to the west, dragging the Spartans further out to sea. Then Alcibiades suddenly turned to fight, and Theramenes and Thrasybulus appeared, seemingly out of nowhere. Theramenes moved south to cut off a Spartan retreat back to the city, and Thrasybulus moved southwest to prevent a Spartan escape out of the Hellespont. Mindarus realized he was trapped and immediately ordered his men to make for the beach at Cleri. Thrasybulus realized what was happening and devised a new strategy, somehow signaling the other two squadrons to attack the beach. The naval battle turned into a land battle as the Athenians followed in pursuit. There was a long, drawn-out struggle among the ships, but when Mindarus was killed, the Spartans and their Persian allies, now surrounded on all sides by the marines of Alcibiades, Theramenes to the east, and Thrasybulus to the west, suddenly broke and fled, giving Athens the victory. In one of the great laconic messages in the history of war reporting, the surviving Spartans sent a brief letter back to Sparta describing the situation: “Ships lost. Mindarus dead. Men starving. Don’t know what to do.”

The Athenians set up two trophies to commemorate their victories, one for the naval victory and one for the victory on land.

The Battle of Cyzicus, coming so soon after Cynossema and Abydos, was huge for the Athenians. The Spartan presence in the Hellespont was ended, and the trade routes that fed Athens were again safe. The Athenians captured Cyzicus and were able to collect tribute from the city and the surrounding areas. The Athenians also established a new fort at Chrysopolis to tax trade that flowed through the Bosporus, and this became an important source of revenue for the cash-strapped city. Despite the disasters in Sicily, the revolts in the empire, and the new challenge of a Spartan navy, seemingly the Athenians had now weathered the worst of the storm.