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.
Al-Abbas ibn Ahmad ibn Tulun Al-ʿAbbās ibn Aḥmad ibn Ṭūlūn was the eldest son of the founder of the Tulunid dynasty, Ahmad ibn Tulun, and heir-apparent until his failed attempt to usurp his father in 879. After a failed attempt to take over Ifriqiya, he was imprisoned in Egypt and executed shortly after the succession of his brother, Khumarawayh, in May 884.