Definition: Cleomenes I (died c. 490 B.C.) was an Agiad king of Sparta. The Agidae traced their lineage back to Heracles. At the start of Cleomenes' reign, Sparta was the dominant power in Greece. Sparta had allies linked to her by individual treaties, but there was no Peloponnesian League. When Cleomenes tried to gather these allies together to go to war in Attica, they refused. The alliances then became the Peloponnesian League (a symmachy) where the poleis sent representatives to an assembly which made binding decisions for all. After a noteworthy reign, including advising the Plataeans to ally with Athens against Boeotia, and leading a coup against Argos in which Cartledge says 6000 Argive warriors were killed, Cleomenes fell out of favor for such things as corrupting the priestess at Delphi or for excessive drinking of neat wine (which was considered a barbarian custom by the temperate Spartans). Eventually, Cleomenes was imprisoned. There he managed to commandeer a knife which he used to commit a gruesome suicide.
His only heir was his daughter Gorgo. This status made her a patrouchos. Gorgo had previously been married to her uncle, Cleomenes younger half-brother Leonidas.
Sources
"Sparta and the Ionian Revolt: A Study of Spartan Foreign Policy and the Genesis of the Peloponnesian League," Jakob A. O. Larsen. Classical Philology, Vol. 27, No. 2. (Apr., 1932), pp. 136-150.Paul Cartledge, The Spartans.
Alternate Spellings: Kleomenes
