Gündoğan, historically Turbessel (Syriac: Tel Bshir; Arabic: Tell Bāshir or Tel-Basheir; Armenian: Թլպաշար, romanized: Tʿlpašar; Turkish: Tilbeşar or Tilbaşar), is a neighbourhood in the municipality and district of Oğuzeli, Gaziantep Province, Turkey.

While the site had been occupied since the Bronze Age, the fort gained importance during the Byzantine Empire and came under control of local Armenian lords in the late 11th century.

In late September 1108, near Turbessel, Tancred, with 1,500 Frankish knights and infantry, and 600 Turkish horsemen sent by Fakhr al-Mulk Ridwan confronted Baldwin II and the 2,000 men of Jawali Saqawa, atabeg of Mosul.

Mawdûd successively besieged Edessa then Turbessel, but had to lift the siege each time, as Joscelin I succeeded in attacking the rearguard of the Turkish army.

[7][8] While Mawdud was besieging Turbessel, Sultan, the Munquidite emir (or ruler) of Shaizar, sent envoys to him, seeking his assistance against Tancred.

[12][13] Following the fall of Edessa in 1144, Joscelin II fled to Turbessel, where he held the remnants of the county west of the Euphrates.

Count Joscelin II was captured shortly after, on May 4, 1150 on his way to Antioch, and Turbessel was again besieged, but fiercely defended by Countess Beatrice of Saone.