 In 479 BC , one year after the famed Battle of Thermopylae , Dilios , a hoplite in the Spartan Army , begins his story by depicting the life of Leonidas I from childhood to kingship via Spartan doctrine . Dilios 's story continues and Persian messengers arrive at the gates of Sparta demanding " earth and water " as a token of submission to King Xerxes ; the Spartans reply by killing and kicking the messengers into a well . Leonidas then visits the Ephors , proposing a strategy to drive back the numerically superior Persians through the Hot Gates ; his plan involves building a wall in order to funnel the Persians into a narrow pass between the rocks and the sea . The Ephors consult the Oracle , who decrees that Sparta will not go to war during the Carneia . As Leonidas angrily departs , a messenger from Xerxes appears , rewarding the Ephors for their covert support . 
