The ruins of Samosata (3rd c), the old Kommagene capital on the Euphrates, now mostly lie submerged beneath the waters of the Ataturk Baraji (Dam) south-west of Kahta. Only when the level in the reservoir is low does the 45m/148ft high castle hill, which in 1990 was still being excavated, break the surface of the water. The site is reached from Adiyaman by driving east to Anil and then south along the new road to Yeni Samsat (about 65km/40 miles). From about 640 Samsat, like Adiyaman, was one of the frontier forts (thugur) constantly changing hands between Byzantium and the Arab and Turkoman invaders, sometimes under Christian occupation (e.g. 700, 860, 1098) and at other times Muslim (10th c. Emirate of Aleppo; 12th c. Seljucks).