Rhemaxos was an ancient king who ruled to the north of Danube around 200 BC and who was the protector of the Greek colonies in Dobruja, receiving a tribute from them in exchange of protection against outside attacks. It appears that the links with the Greek cities lasted a rather long time, as several treaties have been found.
Most historians have suggested that he was the chieftain of a Dacian tribe union on the Romanian Plain.
References
Rhemaxos Wikipedia(Text) CC BY-SA