Editing Cleomenes I (section)

=== Encounter at Plataia (519 BC) ===
The first known deed of Cleomenes as king is his dealing with the city of [[Plataea|Plataia]], located between [[Thebes, Greece|Thebes]] and [[Classical Athens|Athens]]. In 519, [[Herodotus]] states that Cleomenes happened to be in the vicinity of Plataia, when the Plataians requested an alliance with Sparta, which he rejected.  Instead he advised them to ally themselves with Athens, because he wanted to stir a border conflict between Thebes and Athens, two of the most powerful ''poleis'' of central Greece.<ref>Herodotus, vi. 108.</ref><ref name=":7">Ste. Croix, "Herodotus and King Cleomenes", p. 423.</ref><ref>L. H. Jefery, "Greece before the Persian Invasion", in Boardman et al., ''Cambridge Ancient History, vol. IV'', p. 360, thinks he rejected the Plataean offer to join the League because the city was "too remote and small".</ref> The Plataians probably wished to avoid their forced incorporation into the [[Boeotia|Boiotian League]], which was being built by Thebes at this time.<ref>L. H. Jefery, "Greece before the Persian Invasion", in Boardman et al., ''Cambridge Ancient History, vol. IV'', p. 358.</ref><ref name=":2" /> Their Spartan alliance request perhaps indicates that they wanted to become a member of the [[Peloponnesian League]], which was likewise being put in place at this time.<ref>L. H. Jefery, "Greece before the Persian Invasion", in Boardman et al., ''Cambridge Ancient History, vol. IV'', pp. 350–353.</ref><ref>Konecny et al., ''Plataiai'', pp. 26, 27.</ref> [[G. E. M. de Ste. Croix]] and [[Paul Cartledge]] call this move "a master-stroke" of diplomacy,<ref>Ste. Croix, "Herodotus and King Cleomenes", p. 423.</ref><ref>Cartledge, ''Sparta and Lakonia'', pp. 123, 124.</ref> but other modern scholars do not believe it was Cleomenes' intention to create a rift between Thebes and Athens.<ref>Scott, ''Historical Commentary on Herodotus'', p. 376.</ref>

Herodotus does not explain why Cleomenes was near Plataia at that time. A number of theories have been advanced to explain it. Perhaps he was marching on Thebes to support an invasion of his ally, Lattamyas of [[Thessaly]], but as the Thebans had defeated the Thessalians at the Battle of Ceressus before he arrived, he took the opportunity to try and undermine them without engaging his forces.<ref>Buck, ''History of Boeotia'', p. 114.</ref> Another possibility is that he was trying to convince either [[Megara]] or Thebes to join the Peloponnesian League, or he was arbitrating between Megara and Athens over the island of [[Salamis Island|Salamis]].<ref>Roobaert, ''Isolationnisme et Impérialisme'', p. 7, considers these theories as "baseless suppositions" and simply suggests that Cleomenes was on a diplomatic mission to Plataea.</ref><ref>L. H. Jefery, "Greece before the Persian Invasion", in Boardman et al., ''Cambridge Ancient History, vol. IV'', p. 360, thinks he was bringing Megara into the League.</ref><ref>Scott, ''Historical Commentary on Herodotus'', pp. 375, 376.</ref>

The date of this event has been challenged by some modern scholars, who have often suggested 509 rather than 519, as it would better fit with Cleomenes' latter involvement in Athenian politics, but the majority view remains in favour of 519.<ref>Forrest, ''History of Sparta'', p. 85, tends towards 509.</ref><ref>Buck, ''A History of Boeotia'', pp. 113, 114, favours 519.</ref><ref>Ste. Croix, "Herodotus and King Cleomenes", p. 422, supports the date of 519.</ref><ref>Roobaert, ''Isolationnisme et Impérialisme'', p. 6 (note 18), is in favour of 519.</ref><ref>Hornblower, ''Commentary on Thucydides, Volume I'', pp. 464, 465, supports 519.</ref><ref>Konecny et al., ''Plataiai'', p. 26 (note 87), favour 509/508.</ref><ref>Scott, ''Historical Commentary on Herodotus'', p. 375, for 519.</ref>