Samsat (Kurdish: Samîsad,[2] Ottoman Turkish صمصاد Semisat[3]), formerly Samosata (Ancient Greek: Σαμόσατα) is a small town in the Adıyaman Province of Turkey, situated on the upper Euphrates river.

The current site of Samsat is comparatively new, however, being rebuilt in 1989 when the old town of Samosata was flooded during the construction of the Atatürk Dam.

[1] The city of Samosata was founded sometime before 245 BC on the previous Neo-Hittite site of Kummuh by the Orontid king of Sophene, Sames I.

[11] He may have founded the city in order to assert his claim over the area, a common practice amongst Iranian and Hellenistic dynasties, such as Cappadocia, Pontus, Parthia and Armenia.

[12] The city was built in a "sub-Achaemenid" Persian architectural form, similar to the rest of Orontid buildings in Greater Armenia.

[15] Like other early-Orontid royal residences, Samosata experienced a sudden shift in its architectural style under the Orontids of Commagene due to their close involvement in the Greco-Roman world.

[16] During this period, Samosata was most likely populated by a variety of peoples, descended from Arameans, Assyrians, Neo-Hittites, Armenians, and Persians.

[17] Samosata was amongst the places where its ruler Antiochus I Theos (r. 70–31 BC) founded sanctuaries that contained inscriptions about his cult as well as reliefs of his dexiosis with Apollo-Mithras.

The letter makes mention of an Aramaic-speaking elite in Samosata that studied Greek literature and Stoic philosophy.

[22] In June 966, Samosata was the venue of an exchange of prisoners between the Byzantine Emperor Nikephoros II Phokas and his Muslim foe Sayf al-Dawla.

[23] After the collapse of Byzantine authority in the region, the town fell into the domain of the Armenian Philaretos Brachamios.

[24] At some point after that it fell into the hands of a certain Baluk, on of Amīr Ghāzī, who is mentioned among the army of Ridwan of Aleppo which besieged Edessa in 1095.

Earlier bishops included Peperius, who attended the Council of Nicaea (325); Saint Eusebius of Samosata, a great opponent of the Arians, killed by an Arian woman (c. 380), honoured on 22 June; Andrew, a vigorous opponent of Cyril of Alexandria and of the Council of Ephesus.

The first excavations were conducted in 1964 and 1967 under the direction of the American archeologist Theresa Goell in anticipation of the site being flooded by a new dam across the Euphrates at [Halfeti].

[33] Then, in 1977, under the Lower Euphrates Project, plans were put together aimed at identifying and saving the archaeological settlements that were to be inundated by the reservoir of Karakaya and Atatürk Dams.

The following year, the excavations started in 1978, except for 1980, until 1987, under Ankara University, Faculty of Language and History-Geography It was conducted by the team led by Nimet Özgüç.

Coins belonging to the 12th - 13th centuries AD were identified during the excavations in the layers dating to the late phases of the Middle Ages.