Whakaotihia te rerenga e whai ake nei: Ṭāhir ibn Ḥusayn (, "Tâhereben Hoseyn";, "Tahir bin al-Husayn"), e mohiotia ana ko Dhul-Yamīnayn (, "te ambidextrous"), me al-Aʿwar (, "te kanohi kotahi"), he rangatira Iranian me te kawana i te wa o te caliphate Abbasid. Ko te mea nui, i mahi ia i raro i a al-Ma'mun i te wā o te
Ko te tuawha o Fitna me te arahi i nga ope ka hinga i a al-Amin, ka waiho a al-Ma'mun hei "caliph". I whakawhiwhia ia hei kawana o Khorasan, i tohu i te timatanga o te whare rangatira o Tahirid.