Question: Ubaydallah ibn Abdallah ibn Tahir was the last major Tahirid to hold high office in what dynasty?
Sentence (from "Tahirid dynasty"): The Tahirid dynasty (Persian: طاهریان‎ ‎ , "Tâhereyân") was a dynasty, of Persian dihqan origin, that governed the Abbasid province of Khorasan from 821 to 873 and the city of Baghdad from 820 until 891.
Relevant evidence: Yes