At the Battle of Sepeia (; c. 494 BC), the Spartan forces of Cleomenes I defeated the Argives, fully establishing Spartan dominance in the Peloponnese. The Battle of Sepeia is infamous for holding the highest number of casualties within a battle during the classical Greek period. The closest thing to a contemporaneous source for the description of the battle is, as for many events in this time period, the Histories of Herodotus (written approximately fifty years later, c. 440 BC). Herodotus provides context of the political, military and economic landscape of the Peloponnese preluding, during and after the Battle of Sepeia. During the 5th century Sparta was one of the largest military powers in the Peloponnese. This is evident through the Spartans victory over Argos in the Battle of the 300 Champions (546 BC) to gain control over the highly disputed territory of Thyrea. However, the Argives sought revenge on Sparta, seizing back control of Thyrea approximately fifty years after the Battle of the 300 Champions. Ultimately, this reignited tensions between the Spartans and the Argives, driving the two forces to engage in what is now known as the Battle of Sepeia. The Spartan forces were led by the Agiad King Cleomenes I. Cleomenes wished to take action against Argos for their heresy. The King often used religion as a political tool of manipulation to enlist the support of the Spartan people. Thus, Cleomenes sent four Púthιoι to the Oracle of Delphi (also known as Pythia) seeking the oracles support and religious reassurance. Cleomenes proclaimed that the Oracle of Delphi predicted Sparta’s triumph over Argive forces in a future battle. Thus, Cleomenes had gained the religious approval necessary to enlist the support of the Spartan people to fare war on Argos. The Argive forces also sought the advice of the Oracle of Delphi. However, the Oracle foretold the Argives of their looming defeat in a future battle. Thus, the Argives were cautious of their Spartan enemies, and reluctant to engage in battle if not forced to do so. Ultimately, when the Battle of Sepeia began, the foretold predictions by the Oracle of Delphi, dictated the stratagems employed by the Spartans and the Argives respectively. The Argives, cautious of the Spartan’s predicted victory, decided to listen to the Spartan Herald’s commands and copy what the Herald said. This allowed for the Argives to take their meal breaks at the same time