Pontus is a historical Greek designation for a region on the southern coast of the Black Sea, located in modern-day northeastern Turkey. The name was applied to the coastal region in antiquity by the Greeks who colonized the area, and derived from the Greek name of the Black Sea: Πόντος Εύξεινος Pontos Euxeinos ("Hospitable Sea"), or simply Pontos. Having originally no specific name, the region east of the river Halys was spoken of as the country εν Πόντοι en Pontôi, "on the Pontos", and hence acquired the name of Pontus, which is first found in Xenophon's Anabasis. The extent of the region varied through the ages, but generally it extended from the borders of Colchis (modern Georgia) until well into Paphlagonia in the west, with varying amounts of hinterland. Several states and provinces bearing the name of Pontus or variants thereof were established in the region in Hellenistic, Roman and Byzantine times. Pontus is known for the residence of the Amazons, with Amasia is not only applied for a city Amasya but for all of Pontus in Greek mythology.