The leader of the attack was the TyrantCleisthenes 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 writerThessalos. 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 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.
The First Sacred War ended with the victory of the allies of the Amphictyony. Kirrha was destroyed and its lands were dedicated to Apollo, Leto and Artemis and it was forbidden to cultivate them or let animals graze on them. Its inhabitants fled to mountain Kirphe. Cleisthenes was generously rewarded with one third of the booty. In order to celebrate the end of the fighting the first Pythian Games were organized with Cleisthenes playing a major part in them. However, modern scholarship is very sceptical on the exact events and on the long duration of the war.
