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-Mahdi Abdallah Al-Mahdi Abdallah (1793 - 28 November 1835) was an Imam of Yemen who ruled from 1816 to 1835. He belonged to the Qasimid family, who were descendants of the Prophet Muhammad. From 1597 to 1962, the Qasimids dominated the Zaidi imamate of Yemen.