Ephors were
Spartan overseers. There were five of them. Each ephor was elected from the
Spartans over 30 for one year. They could only serve in the office once. The election procedure involved the
Spartans attempting to cheer the loudest for the candidate they wanted. People who did not know who the
chanting was for would judge the volume, and those men that had recieved the loudest chanting would become the ephors.
The ephors were involved in the day to day running of Sparta. They were subject to no written laws, only customs and traditions, and the need for a majority vote. The belief was that they could be kept in check by the knowledge that at the end of the year they would be out. Their duties included the organisation of the education system, and control of the helots. They were also responsible for ambassadorial relations with other states. They acted as judicial officials.
Probably the most likely reason for their existence, was to act as a balance to the kings. The elegibility of every Spartan suggests it to be an anti-aristocratic position. Every month they would swear oaths to the kings, to keep Sparta stable, in return for the kings abiding by the laws. Every few years the ephors would go out and obseve the sky at night, looking for omens as the the king's success. If a bad omen was seen, they could exile the king. Two ephors were also expected to accompany the king on campaigns.
However, the ephors only held office for one year, unlike the king, and this suggests that it would be impossible for the ephors to contol the kings, due to the kings greater unspoken power and influence.