From the Archives - How Cock Fighting Came to Athens
During the “Golden Age” of Athens, cock fights were staged annually at state expense in the city’s theatre. The source of this custom was an incident that occurred as the Athenians were on the march in Central Greece to join the Hellenic Army that would defeat the Persians invaders in the Battle of Plataea (c. August 20-25, 479 BC). As told by the Romano-Greek scholar Claudius Aelianus (fl., c. AD 175- c. 235), in his collection of Historical Miscellany,
When Themistocles went forth with an army of the citizens against the Persians he saw some cocks fighting; neither did he behold it slightly, but turning to the whole army said, "These undertake this danger, neither for their country, nor for their country’s gods, nor for the monuments of their ancestors, nor for fame, liberty, or their children; but that they may not be worsted, or yield one to the other."
Apparently the Athenians took these words to heart, and helped win the battle, which decisively crushed the Persian threat to Greece. To commemorate the incident, Themistocles arranged for the city to hold the annual cock fights.