Ubaydallah ibn Abdallah ibn Tahir was the last major Tahirid to hold high office in what dynasty?
Ubaydallah ibn Abdallah ibn Tahir Abu Ahmad Ubaydallah ibn Abdallah ibn Tahir (Arabic: أبو أحمد عبيد الله بن عبد الله بن طاهر‎ ‎ , ca. 838 – May 913) was a ninth century Tahirid official and military officer. He was the last major Tahirid to hold high office, having served as the governor of Baghdad at various points between 867 and 891.
Ubayd Allah ibn Yahya ibn Khaqan Abū al-Ḥasan ʿUbayd Allāh ibn Yaḥyā ibn Khāqān was an Abbasid official who served twice as vizier, under caliphs al-Mutawakkil and al-Mu'tamid.