In ancient Greece, Sparta was unique in having a dual kingship - two kings from different clans, the Agiads and the Eurypontids, reigning simultaneously. The institution was already well-developed by the 8th century BC, when Theopompos of the Eurypontid clan emerges as the first recorded Spartan king. At least fifty-seven men held office as Spartan king between Theopompos and the Agiad Kleomenes III who died in 222 BC. For almost all this period the Spartan kingship was primarily a military office, and thus the kings embody much of the military history of Sparta. Wherever Sparta's main battles took place, there the kings were. Naturally, the character of the particular king would often determine the outcome of a battle or campaign. Leonidas I at Thermopylai was one example.
