Sebasteion is one of the most significant archaeological discoveries that have been made in recent years. It was brought into daylight in 1979. It was It was built in 1C AD and was dedicated to Imperial Sebastos (Greek equivalent of the Latin Augustus).

Sebasteion consisted of a 14-meter-wide courtyard and two parallel three-storied porticoes with a length of 80 m, of half-columns on both sides. The north portico was highly damaged with the earthquakes of the 4th century; therefore many of the reliefs decorating its intercolumniations are missing. Each storey of the south portico had different column style. The first storey was Doric; the middle was Ionic, and the third storey, smaller Corinthian half columns.