The first Turkish vizier of the Abbāsids Ubayd Allāh b. Yaḥyā

For the first time in Islamic history, the institution of the visierate, which first emerged as an organized structure with in the Abbāsid State, became the highest-ranking unit of government after the caliph. Recognizing the power of the vizierate, many individuals and their families competed to attain this position. In these competitions, al-Furat and al-Jarrah families were in the forefront. During the Sāmerrā Period, the Khāqānid family became a part of this competition too when Caliph al-Mutawakkil named Ubayd Allāh b. Yaḥyā as the vizier. However, amongst the Khāqānid family, Ubayd Allāh was the only person to successfully fulfill this role. Thus, Ubayd Allāh, who emerged from the Turks a fundamental element of the Sāmerrā Period, became the first turkish vizier in the Abbāsid history upon his appoinment. Due to his political intelligence and accounting skills, he successfully eliminated plans against him and served as a vizier for many years. Having served through two different caliph periods, his brightest one was during Caliph al-Mutawakkil's reign. During this period, he exerted his influence on Mutawakkil's decisions, especially alongside Fath b. Khāqān. The most significant of these decisions was the removal of al-Muntasir from the first heir apparent position and his replacement with al-Mu'tazz. The events that unfolded with al-Mu'tazz becoming the first heir apparent led to Mutawakkil's demise and plunged the state into irreversible events. Ubayd Allāh also served as vizier reign of Caliph Muʿtamid, because of his exceptional talent in accounting. However, the periods economic hardships, riots and strong opposition caused his efforts to be not as effective as they used to be during the al-Mutawakkil period. After Ubayd Allāh, his sons and grandchildren held many administrative positions with visier and scribe. However, they were dismissed from their duties shortly after, as they lacked the necessary qualifications for administrative tasks. After the time of Muhammad b. Ubayd Allāh, the institution of the vizierate was shaken and became unable to fulfill its functions. Keywords: Abbāsids, Sāmarrā, Viziera, Ubayd Allāh b. Yaḥyā.