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...