The Fall of Turbessel occurred in 1151 when the Turks seized Turbessel as well as other possessions that Joscelin II had just ceded to the Byzantines.[1][2]
Following the fall of Edessa, Joscelin I] made Turbessel his new capital.[2] He was taken captive by Nur ad-Din Zengi in 1150 and his wife, Beatrice de Saone took over; however, she was forced to cede Turbessel and other possessions to the Byzantines.[2][3]
In the spring of 1151 Nur ad-Din allied with Mesud and invaded the Byzantine territories, joined by Timurtash and Kara Arslan.[1] The Byzantine garrisons were unable to resist the attacks and as a result Timurtash now ruled in Bira, Samosata, Cafersoud, Khourous and Qal’at ar-Rum, Mesud in Aintab and Duluk and Nur ad-Din in Azaz, Cyrrhus, Krak des Chevaliers, Tall-Khalid, Ravendan, Hisn Kerzin and Nahr al-Djauz.[1] As well as Turbessel, Burj-ar-risas and Kafarlatha also fell to the Turks.[1]