al-Muwaffaq
... that al-Muwaffaq was the effective ruler of the Abbasid Caliphate for twenty-one years, sidelining his brother, the Caliph al-Mu'tamid?
... that <b id="mwBNU"><a href="./Al-Muwaffaq" id="mwBNY" rel="mw:WikiLink" title="Al-Muwaffaq">al-Muwaffaq</a></b> was the effective ruler of the <a href="./Abbasid_Caliphate" id="mwBNc" rel="mw:WikiLink" title="Abbasid Caliphate">Abbasid Caliphate</a> for twenty-one years, sidelining his brother, the Caliph <a href="./Al-Mu'tamid" id="mwBNg" rel="mw:WikiLink" title="Al-Mu'tamid">al-Mu'tamid</a>?