The city was founded by the Roman emperor Trajan (r. 98–117) near the ancient town of Doriscus, and received his name. In the Roman period, the city was famous for its baths.
In the 4th century, it became the capital and metropolitan see of the Thracian Roman province of Rhodope. Under Justinian I (r. 527–565) the city walls were repaired. The city remained the metropolis of the ecclesiastical province of Rhodope until its decline in the 14th century, but ceased being a provincial capital with the rise of the theme system, coming under the Theme of Macedonia, although a single strategos of Traianoupolis is attested in an 11th-century seal. In autumn 1077, the troops of the rebel general Nikephoros Bryennios the Elder proclaimed him emperor at Traianoupolis.
In the Partitio Romaniae of 1204 it is listed as the pertinentia de Macri et Traianopoli. The Crusader Geoffrey of Villehardouin is known to have been assigned fiefs in the area. In 1205 or 1207, the town was destroyed by Tsar Kaloyan of Bulgaria, but in 1210 it is attested as a Latin (Roman Catholic) archbishopric. Following its recovery by the Empire of Nicaea, the Greek Orthodox see was restored; in 1260, John Kondoumnes was named as its bishop. The area was ravaged by Bulgarian raids in 1322 and by Turkish raids in 1329/30. By the time John Kantakouzenos and his ally, Umur Bey, erected their camp on the site in the winter of 1343/44, the city had lain destroyed and abandoned for several years. In 1347, the local metropolitan was therefore allowed to reside in Mosynopolis instead. The area fell to the Ottoman Turks by 1365, and in 1371 the see was supplanted by that of Serres in the ecclesiastical hierarchy.
The sole use of the site after the city’s abandonment was as a way-station, and in ca. 1375/85, the Ottoman Gazi Evrenos built an inn (Hana) and a Turkish bath, which still survive. Traces of the medieval buildings and the circuit wall also survive.
The area came under Bulgarian rule after the Balkan Wars of 1912–13 and was ceded to Greece in the Treaty of Neuilly (1919).