former border with Macedonia was shifted from the Struma River to the Mesta River. This usage lasted until the Roman conquest. Henceforth, (classical) Thrace referred only to the tract of land largely covering the same extent of space as the modern geographical region. In its early period, the Roman province of Thrace was of this extent, but after the administrative reforms of the late 3rd century, Thracia's much reduced territory became the six small provinces which constituted the Diocese of Thrace. The medieval Byzantine theme of Thrace contained only what today is East Thrace. Cities The largest cities of Thrace are: Istanbul, Plovdiv, Çorlu, Tekirdağ, Burgas, Edirne, Stara Zagora, Sliven, Yambol, Haskovo, Komotini, Alexandroupoli, Xanthi, and Kırklareli. Demographics and religion Most of the Bulgarian and Greek population are Orthodox Christians, while most of the Turkish inhabitants of Thrace are Sunni Muslims. Ancient Greek mythology Ancient Greek mythology provides the Thracians with a mythical ancestor Thrax, the son of the war-god Ares, who was said to reside in Thrace. The Thracians appear in Homer's Iliad as Trojan allies, led by Acamas and Peiros. Later in the Iliad, Rhesus, another Thracian king, makes an appearance. Cisseus, father-in-law to the Trojan elder Antenor, is also given as a Thracian king. Homeric Thrace was vaguely defined, and stretched from the River Axios in the west to the Hellespont and Black Sea in the east. The Catalogue of Ships mentions three separate contingents from Thrace: Thracians led by Acamas and Peiros, from Aenus; Cicones led by Euphemus, from southern Thrace, near Ismaros; and from the city of Sestus, on the Thracian (northern) side of the Hellespont, which formed part of the contingent led by Asius. Ancient Thrace was home to numerous other tribes, such as the Edones, Bisaltae, Cicones, and Bistones in addition to the tribe that Homer specifically calls the "Thracians". Greek mythology is replete with Thracian kings, including Diomedes, Tereus, Lycurgus, Phineus, Tegyrius, Eumolpus, Polymnestor, Poltys, and Oeagrus (father of Orpheus). Thrace is mentioned in Ovid's Metamorphoses, in the episode of Philomela, Procne, and Tereus: Tereus, the King of Thrace, lusts after his sister-in-law, Philomela. He kidnaps her, holds her captive, rapes her, and cuts out her tongue. Philomela manages to get free, however. She and her sister, Procne, plot to get revenge, by killing her son Itys (by Tereus) and serving him to his father for dinner. At the end of the