[2] Yazid's loyalty was rewarded by al-Hadi with his appointment to the governorship (ostikan) of Arminiya (a large province encompassing the whole of Transcaucasia), which he governed until 788/789.
[3] His rule was harsh towards the native Christian population, and he carried out large-scale colonization of the province, particularly at Shirvan, with Arab Muslims.
[1] He was also the first of a long line of Shaybanid ostikans, beginning with his sons, and hence the progenitor of the Mazyadid dynasty that ruled in Shirvan as autonomous and later independent emirs (Shirvanshahs) until 1027.
[4] After his tenure in Arminiya, Yazid was sent to combat a Kharijite rebellion led by the fellow-Shaybanid al-Walid ibn Tarif (795/796).
[2][4] Yazid was re-appointed as ostikan in 799, in time to face the last Khazar attack on the Caliphate's Caucasian provinces, which he defeated.