The First Sacred War or Cirraean war, was fought between the Amphictyonic League of Delphi and the city of Kirrha. In the beginning of the 6th century B.C. the attempt of the Pylaeo-Delphic Amphictyony, controlled by the Thessalians, to take hold of the Sacred Land (or Kirrhaean Plain) of Apollo ended up in this war. Its end was marked by the organization of the first Pythian Games. The conflict arose due to Kirrha's frequent robbery and mistreatment of pilgrims going to Delphi and their encroachments upon Delphic land. The war resulted in the defeat and destruction of Kirrha. The war is notable for the use of chemical warfare at the Siege of Kirrha, in the form of hellebore being used to poison the city's water supply.