The history of the city began in the mid-6th century BC when an earlier settlement of the second and early first millennia BC, frequented by local Colchian tribes, was replaced by the Milesian Greek colony of Dioscurias (). The city is said to have been founded and named by the Dioscuri, the twins Castor and Pollux of classical mythology. According to another legend it was founded by Amphitus and Cercius of Sparta, the charioteers of the Dioscuri. Arrian wrote that it was a colony of Miletus.