One of the foremost prose-writers and poets of the fourth/tenth century, Ibn ʿAbbād was also an able politician and administrator and a great patron, a kātib who for more than eighteen years successfully held office as vizier to a branch of the Buwayhid family. Biographical sources are agreed upon his name (ism) and genealogy (onasab): Ismaāʿīl b. ʿAbbād b. al-ʿAbbās b. ʿAbbād b. Aḥmad b. Idrīs. They also agree on his agnomen (kunyah), Abū ʿl-Qāsim, which must have been given to him in childhood, since he had no son. Varying explanations are given of the honorific title (Jaqab) of al-Ṣāḥib usually prefixed to his name. Some sources say that the form of the title was originally ṣāḥib Ibn al-ʿAmīd, “the companion of Ibn al-ʿAmīd”, because it was Abū ʿl-Faḍl Ibn al-ʿAmīd, vizier to the Buwayhid amir Rukn al- Dawlah, who had trained him as a kātib. Others claim that the title in its full form was ṣāḥib Muʿayyid al-Dawlah, and that it was given in recognition of Ibn ʿAbbād's loyalty to the Buwayhid amir of that name. Whatever the true explanation, it was soon forgotten, and the title al-Ṣāḥib thereafter entered the repertory of Muslim honorifics. The zeal and efficiency with which Ibn ʿAbbād discharged his duties as vizier also earned him the more formal title of Kāfī ʿl-Kufāh, “the most competent of the competent”.