Sebastopolis (Sulusaray) is about 68 kilometers (42 miles) from the center of Tokat, and about 30 kilometers (19 miles) from Artova town. The site is situated on a plain surrounded by mountains and the river of Cekerek runs near it. The site is at the crossroads of east to west route and south and central to north route. This shows the importance of the city during the Roman and Byzantine periods.

The foundation of this ancient city is still unknown. Some sources say that it was first established in the first century AD during the Roman emperor Trajan's period, and that the city was separated from the Pontus Galaticus Polaminiacus districts and was included in the Cappadocia region. There is an epitaph (inscription rock with several rows of writings carved on it) about this. The epitaph was written as a monument for the Arrian, the Governor of Cappadocia.

The word Sebastopolis comes from Greek; "Sebasto" means huge, great or magnificent, and "Polis" means city. So, Sebastopolis means "Great City". In some resources the city was named as Heracleopolis. Heracleopolis means the city of Heracles, a pagan god symbolizing power and strength in the Greek and Roman mythology.

Architectural pieces recovered during the diggings organized by the Directorate of the Tokat Museum in 1987, showed that the city was an important settlement during the Hellenistic, Roman and Byzantine periods. The artifacts recovered at the Comana Pohtica (Old Tokat) are very similar to those recovered from the city of Sebastopolis, probably these two ancient cities had a close relationship in the past.

The ancient city was surrounded by a city wall made of small, neatly cut stones put together without using mortar. A circular shape temple was discovered at the northeast side of the city, it was made of marble floor. The baths are situated at the eastern part of the Sebastopolis, where the water needed was recovered from the thermal spring located about 3 kilometers (1,9 miles) to the southwest. Many statues and statuettes, friezes, columns, grave steles and epitaphs have been found during excavations.