Eskişehir (USˌɛskɪʃəˈhɪər , esˈciʃehiɾ; from eski 'old' and şehir 'city') is a city in northwestern Turkey and the capital of the Eskişehir Province. The urban population of the city is 898,369 with a metropolitan population of 797,708. The city is located on the banks of the Porsuk River, 792 m above sea level, where it overlooks the fertile Phrygian Valley. In the nearby hills one can find hot springs. The city is to the west of Ankara, to the southeast of Istanbul and to the northeast of Kütahya. It is located in the vicinity of the ancient city of Dorylaeum. Known as a university town; Eskişehir Technical University, Eskişehir Osmangazi University, and Anadolu University are based in Eskişehir. The province covers an area of . The name Eskişehir can be literally translated as 'Old City' in Turkish. The name has been documented in Ottoman records since the late 15th century. The city was founded by the Phrygians in at least 1000 BC, although it has been estimated to be older than 4000 years old. The current city lies about a mile from the ancient Phrygian city of Dorylaeum. Many Phrygian artifacts and sculptures can still be found in the city's archeological museum. There is also a museum of meerschaum stone, whose production remains still notable, used to make high quality meerschaum pipes. In the fourth century AD the city moved about ten km northeast, from Karacahisar to Şehirhöyük. The region was originally inhabited by Hittites. Many ancient geographers described the city as one of the most beautiful in Anatolia. As with many towns in Anatolia, Christianity arrived after Constantine the Great legalized the religion in the Roman Empire. Beginning in the 4th century, records exist of bishops holding office in Eskişehir. The city was known as Dorylaeum (Δορύλαιον) in Greek in that period. One of these bishops, Eusebius, was heavily involved in shaping the evolving dogma of the church. It was called Sultanönü during the Seljuk period.