Battle of Deres - 640 B.C.
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.
All from Pausanias (geographer) 4.15.4