around Hasankeyf was likely part of the Hurrian kingdoms. The Akkadian and Northwest Semitic texts of the Mari Tablets (1800–1750 BC) refer to Ilānṣurā, an important walled city on a large river. Ilānṣurā has been tentatively identified with Hasankeyf, although several locations in northeast Syria have also been proposed. Late Bronze Age By the 14th century BC, the Hasankeyf area was within the Hurrian kingdom of Mitanni. Between the 9th and 7th centuries BC it was part of the Neo-Assyrian Empire, and by the mid-6th century it was part of the Median empire. Roman and Byzantine empires In Roman times, Hasankeyf (known as Kepha, Cephe, Cepha or Ciphas) was a base for legionaries on the frontier with the Sasanian Empire of Persia. For a time the town became the capital of the Roman province of Arzanene, although Nisibis was the headquarters of the Dux Mesopotamiae. Constantius II (324–361) built a fort at Kepha, but it is unclear whether this was on the current citadel site. The existence of a Roman bridge across the Tigris at Hasankeyf has been viewed as "highly probable" by one scholar who speculates that (like the later bridge) it may have had "a wooden superstructure based on piers of masonry and natural stone". However, none of the remaining structure of the bridge appears to date from Roman times. The balance of power in the region shifted significantly in 363. Following the death of the emperor Julian at the Battle of Samarra, his successor Jovian was forced to surrender to the Persian King Shapur II the eastern provinces of Arzanene, Moxoene, Zabdicene, Corduene and Rehimena. This included 15 castles, along with the cities of Singara and Nisibis, but not their inhabitants, and the fortress of Castra Maurorum. While Kiphas had been administered as part of Arzanene up to 363, it lay on the south bank of the Tigris and was not surrendered to the Sasanians. Before the treaty, the fort at Kiphas had been on the border between Roman territory and the Armenian vassal kingdom of Arzanene. Now the border with Persia ran along the Tigris and the legionnaires at Kiphas were stationed right on it. Their role was chiefly to protect the Tur Abdin massif and the approach through it to the Roman province of Sophanene from attack by the Persians in Arzanene. Recording the situation at the end of the fourth century, the Notitia Dignitatum