Turbessel, known in Arabic as Tall Bāshir (mod. Tellbasar Kalesi, Turkey), was a castle and town in northern Syria in the valley of the Sājūr, a tributary of the Euphrates. During the Frankish period Turbessel was one of the most important strongholds of the county of Edessa and was the seat of its greatest lordship from 1101 to 1113.
The castle is sited on a high, steep mound (partly artificial), about 350 meters (c. 1,150 ft.) long; in the crusader period the town was also defended by a wall. It was a minor Byzantine center after its reconquest from the Muslims by Emperor Nikephoros I in 962, and it was repopulated by Armenians. It was captured by the Saljūq sultan Malik Shāh in 1086, but during the First Crusade (1096-1099) it was taken by Baldwin of Boulogne in 1097 with local support. On his departure for Edessa (February 1098) Baldwin gave it to a local Armenian lord, Fer; and then, with Ravendel, to Godfrey of Bouillon, who based himself there in the summer of 1098. In 1101 Baldwin II of Edessa granted it to his cousin Joscelin I of Courtenay as the main seat of a fief covering all of the lands of the county of Edessa west of the Euphrates.
Turbessel was a base for raids into Muslim territory and became very wealthy, so much so that Baldwin confiscated it from Joscelin in 1113. Thereafter it formed part of the count’s own domain, and after Joscelin succeeded to the county (1119) when Baldwin became king of Jerusalem, the counts tended to live there rather than in Edessa. Turbessel was probably also the usual residence of the Latin archbishops whose nominal see was at the smaller town of Duluk further to the north.
Turbessel’s strategic position also attracted raids: it was briefly besieged by the army of Mawdūd of Mosul in 1111; the region was raided by the Artūqid ruler īlghāzi in 1120; it was threatened by the Byzantine emperor John II Komnenos in 1142. After the capture of Count Joscelin II by the Turks in 1150, Turbessel was defended by his wife, Beatrix, against the Saljūq sultan Ma‘sūd andNūr al-Din. Beatrix sold the castle to the Byzantine emperor, who sent a garrison to occupy it, but in July 1151 it surrendered to Nūr al-Din’s general Hassan al-Manbiji. It remained in the hands of followers of the Zangids until a brief occupation by the Saljūq sultan ‘Izz al-Din Kay-Kāwūs in 1218, after which it belonged to Ayyūbid princes.
The town flourished until the Mongol invasion of Hülegü in 1260. It may have been briefly given to the Armenian king, Het‘um I, but by 1263-1264 it was held by the Mamlūk sultan Baybars I, who demolished the castle. An Arab geographer writing at this time, Ibn Shaddād, describes Turbessel as having been rich and fertile but as being by then depopulated apart from a group of Turcoman nomads; it still possessed a Mamlūk governor, and some of the dependent villages remained settled. The town was sacked by the army of the Turkic conqueror Timur in 1400, after which the Mamlūks no longer maintained a garrison there.