The leader of the attack was the
Tyrant Cleisthenes of
Sicyon, who used his powerful navy to blockade the city's port before using an allied Amphictionic army to besiege Kirrha. The Athenians also participated with a contingent led by Alcmaeon. On the Thessalian side, the leaders were Eurylochos and Hippias. What transpired after this is a matter of debate: the earliest, and therefore probably most reliable, account is that of the medical writer
Thessalos. He wrote, in the 5th century BC, that the attackers discovered a secret water-pipe leading into the city after it was broken by a horse's hoof. An
asclepiad named
Nebros advised the allies to
poison the water with
hellebore, which soon rendered the defenders so weak with
diarrhea that they were unable to resist the assault. Kirrha was captured and the entire
population was slaughtered. Nebros was considered an ancestor of
Hippocrates, so this story has caused many to wonder whether it might not have been guilt over his ancestor's use of poison that drove Hippocrates to establish the
Hippocratic Oath. Later historians told different stories. According to
Frontinus, who wrote in the 1st century AD, after discovering the pipe, the Amphictionic League cut it, leading to great thirst within the city. They then restored the pipe and the desperate Kirrhans immediately began drinking the water, unaware that Kleisthenes had poisoned it with hellebore. According to
Polyaenus, a writer of the 2nd century the attackers added the hellebore to the
spring from which the water came. Polyaenus also gave credit for the strategy not to Kleisthenes but to General
Eurylochus, who he claimed advised his allies to gather a large amount of hellebore from
Anticyra, where it was abundant. The stories of Frontinus and Polyaenus both have the same result as Thessalos's tale: the defeat of Kirrha. The last major historian to advance a new story of the siege was
Pausanias, who was active in the 2nd century. In his version of events,
Solon of Athens diverted the course of the
River Pleistos to avoid passing through Kirrha but the enemy was able to get enough water from their wells and rainwater collection. Solon then added a great quantity of hellebore to the water of the Pleistos and let it flow into Kirrha. ==Outcome of the War==