What is "at-ta'i"

Al-Ta'i (932 – 3 August 1003) was the Abbasid Caliph in Baghdad from 974 to 991. Very little is known about his personal and official life. During his Caliphate, Syria was torn by contending factions — Fatimid, Turkish, and Carmathian; while the Buwayhid dynasty was split up into parties that were fighting among themselves. To top this all off, the Byzantine Emperor John Tzimisces stormed the east in a victorious campaign in 975. After holding the office for seventeen years, al-Ta'i was deposed in 991 by the Buwayhid emir Baha' al-Dawla.