Rioni River
Known to the ancient Greeks as the "Phasis River", Rioni was first mentioned by Hesiod in his Theogony (l.340); Plato has Socrates remark: "I believe that the earth is very large and that we who dwell between the pillars of Hercules and the river Phasis live in a small part of it about the sea, like ants or frogs about a pond" ("Phaedo", 109a). Later writers like Apollonius Rhodius (Argonautica 2.12.61), Virgil (Georgics 4.367) and Aelius Aristides ("Ad Romam" 82) considered it the easternmost limit of the navigable seas. Socrates in "Phaedo" 109a referred to the portion of the world he knew of as between the Pillars of Hercules and the River Phasis, while Herodotus and Anaximander considered Rioni as a boundary between Europe and Asia The famed voyage of Jason and the Argonauts, though semi-mythological, was said to have occurred by the Argonauts sailing up the Rioni River from its mouth at the Black Sea at Poti, to Kutaisi, Georgia.