`Abbasid caliph reigning from 279/892 to 289/902, the son of al-Muwaffaq.
Starting in 267/880-1, al-Mu`tadid led operations against the Zandj under his father. He suffered humiliation, along with Khumarawayh at the Battle of the Mills in 271/885, Khumarawayh came out victorious after both commanders had fled the battlefield early on. His abilities though gave him a military following, demonstrated in 275/888-9 when his father attempted to have him arrested only to face resistance from the military.
After al-Muwaffaq's death in 278/891, al-Mu`tadid received his father's position in the line of succession from al-Mu`tamid along with al-Mufawwad. He also inherited a number of his father's supporters within the administration. In 279/892, al-Mufawwad was removed from his position as heir apparent and six months later al-Mu`tadid accended to the caliphate with little opposition upon the death of al-Mu`tamid..
Like his father, al-Mu`tadid received much of his power from his strong ties to the military. He used his close ties to military leaders to reassert the authority of the caliphate in the central lands of Iraq and al-Jazira, leaving Khurasan, Syria, and Egypt to the Saffarids and Tulunids respectively, making agreements with their leaders that gave up `Abbasid control of lands but provided for peace.
It was during al-Mu`tadid's reign that Baghdad was reestablished as the `Abbasid capital.
During his reign, al-Mu`tadid was able to keep the growing Qarmati threat down to assorted small scale rebellions through his strong arm tactics.
al-Mu`tadid died in 289/902, leaving the caliphate in the hands of his son, al-Muktafi who had been governor of Rayy and al-Jazira under his father.
Kennedy, Hugh. "al-Mu`tadid bi'llah". in EI2.
267 - al-Mu`tadid leads his first military opperations against the Zandj.
271 - al-Mu`tadid faces a humiliating defeat at the hands of Khumarawayh at the Battle of Mills.
275 - al-Muwaffaq tries having his son, al-Mu`tadid, imprisoned, but the military demonstrates in al-Mu`tadid's favor.
278 - al-Muwaffaq's death puts al-Mu`tadid in the line of succession to the caliphate after al-Mu`tamid, behind al-Muwaffad.
279 - al-Mu`tadid moves ahead of al-Muwaffad in the line of succession just six months before al-Mu`tamid dies, making al-Mu`tadid the new caliph.
289 - al-Mu`tadid dies.