The Battle of Deres was a fight between the Spartans and the Messenians, which occurred c. 640 BC, it was the first major military engagement of the Second Messenian War. The Spartans and Messenians didn't have any allies at the time of conflict and the outcome of the battle was highly disputed. After the battle, the Messenians offered Aristomenes the crown of Messenia. Aristomenes declined the offer, preferring instead to become general with absolute powers .In the first year after the revolt the Messenians engaged the Lacedaemonians at a place called Derae in Messenia, both sides being without their allies. Neither side won a clear victory, but Aristomenes is said to have achieved more than it seemed that one man could, so that, as he was of the race of the Aepytidae, they were for making him king after the battle. As he declined, they appointed him general with absolute power.
This battle did not take place at the Lakonian Dereion, but one would expect Derai to mean a 'small hill'. the place-name Dera occurs in a fragmentary late second century Messenian inscrption, which appears to have been a definition of the Messenian borders with Arkadia, otherwise, nothing else is known about this place.