Pontus (/ˈpɒntəs/; Greek: Πόντος, ""sea"") is a historical Greek designation for a region on the southern coast of the Black Sea, located in modern-day eastern Black Sea Region of Turkey. The name was applied to the coastal region and its mountainous hinterland (rising to the Pontic Alps in the east) 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 [Euxeinos] 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 periods, culminating in the late Byzantine Empire of Trebizond. Pontus is sometimes considered as the home of the Amazons, with the name Amasia not only used for a city (Amasya) but for all of Pontus in Greek mythology.