The Battle of the 300 Champions was a battle fought in roughly 546 BC between Argos and Sparta. Rather than commit full armies both sides agreed to pitting 300 of their best men against each other. Both sides would not allow for any injured men to be taken. The day called for complete destruction of the enemy force for victory. The two armies were evenly matched and neither could gain the upper hand. After a bloody battle only three men remained, two Argives and one Spartan. The Argives left the battlefield believing that they had killed all of the Spartans, but they made one mistake. Orthryades, an injured Spartan had still survived and was technically the last man standing on the battlefield for either army claimed victory. He survived long enough to tell his baggage handlers of his victory, and then he committed suicide. The reason for the suicide is up for debate, but the act is of great importance. Orthryades did not die by an Argive sword, and the Spartans could always claim that he survived the battle and killed himself in shame, thus gaining an upper hand due to this act of honor.
Argos did not take too kindly to the Spartans claiming victory and sent their entire hoplite army which was met by a Spartan force of equal magnitude. The Spartans won a decisive victory and as a result gained control of Thyreatis.
Years later, in 420 BC during a lull in the Peloponnesian War, Argos challenged Sparta to a rematch of the Battle of the 300 Champions. Sparta declined.
1. "The Spartans: The World of the Warrior-Heroes of Ancient Greece"- Paul Cartledge. Pgs. 87-88.