Panion (Greek: Πάνιον) or Panias (Πανιάς), in early Byzantine times known as Theodosiopolis (Θεοδοσιούπολις) and in later Byzantine and Ottoman times Panidos (Greek: Πάνιδος, Turkish: Banıdoz), was a town in Eastern Thrace on the coast of the Marmara Sea, on the site of the modern settlement of Barbaros in Tekirdağ Province, Turkey.
[4] The name of Theodosiopolis apparently survived until the middle Byzantine period, as a—now lost—border marker with the inscription kastron Theodospolis is known from the 8th/10th century.
[1] In 813, the town was one of the few settlements that were able to successfully resist the invasion of the Bulgarian ruler Krum, due to its strong and well-maintained fortifications and the numerous inhabitants, who assisted in the defence.
[9] A gravestone dated 27 February 965 mentions a Basil Diakonos, who founded a church dedicated to the Holy Unmercenaries, probably in the town.
[9] The 12th-century traveller and geographer al-Idrisi visited the city of (Banedhos) in the middle of the century, and praised its spacious streets and its shops.
[9] Bishop Ignatius is attested in 1351–1368, during which time the area fell to the Ottoman Turks; Panion itself was occupied without resistance by the future sultan Murad I in 1359.
[12] The town was returned to Byzantine control in the 1403 Treaty of Gallipoli, but some Turkish troops may have remained garrisoned there.