Answer: He defiled it by decapitating it and putting Leonidas' head on a stake.
Step-by-step explanation:
King Leonidas I of Sparta is one of the most famous kings in history due to his heroic stand against the Persians who may have numbered in their hundreds of thousands with a comparatively lower force.
After the Greeks were betrayed and about to be routed, Leonidas was killed in the ensuing battle after which Xerxes ordered that the head be decapacitated and put on a stake, an act which went against Persian customs.