The conspiracy of Cinadon was an attempted coup d'état which took place in Sparta in 399 BCE early in the reign of Eurypontid King Agesilaus II (400–c.
The leader was Cinadon (Ancient Greek: Κινάδων), who was a trusted member of the king's bodyguard, but not a full citizen.
Although elaborately organized, the plot was in the end betrayed to the ephors; they cracked down on the conspirators, and Cinadon himself was punished, possibly executed.
Cinadon thus indicated that only 40 people present were peers – comprising the king, ephors, gerousia, and other full citizens, and that these 40 were significantly outnumbered.
[8] The informer added that while only some conspirators were armed, the rest had access to tools and implements that could serve as makeshift weapons, such as axes and sickles.
[11] Polyaenus, in his short version of this event (cited above), added that the when the ephors received word from Aulon, they "ordered the execution of the other conspirators while he was still absent, and in this way they suppressed the conspiracy without any resistance".