A King Chosen by Accident of Succession

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

Leonidas I was a king of Sparta from the Agiad royal line, one of the city's two hereditary dynasties, both of which Spartan tradition traced back to the hero Heracles. He came to the throne unexpectedly around 490 BCE: he had two elder brothers, Cleomenes and Dorieus, neither of whom left a male heir, Dorieus having died campaigning in Sicily, and Leonidas was already married to Cleomenes's own daughter Gorgo, herself remembered for her own political shrewdness in the ancient sources that survive.

That succession by default rather than design is itself part of what makes Leonidas's later reputation notable: a king who reached the throne because two more direct heirs failed to produce sons, rather than through any contest for the office, went on to become the single most remembered Spartan king in the historical record, his name outlasting every other Agiad or Eurypontid ruler of the period by a wide margin. The historicity of the man himself is not in question, unlike many figures from the same broader period whose lives survive only in later legend; Leonidas's reign and death are documented by Herodotus, writing within living memory of the events.