al-Fadl ibn al-Rabi'
... that the Abbasid vizier al-Fadl ibn al-Rabi' was the main instigator of the civil war between brothers and rival caliphs al-Ma'mun and al-Amin?
... that the <a class="mw-redirect" href="./Abbasid" id="mwDLA" rel="mw:WikiLink" title="Abbasid">Abbasid</a> <a href="./Vizier" id="mwDLE" rel="mw:WikiLink" title="Vizier">vizier</a> <b id="mwDLI"><a class="mw-redirect" href="./Al-Fadl_ibn_al-Rabi'" id="mwDLM" rel="mw:WikiLink" title="Al-Fadl ibn al-Rabi'">al-Fadl ibn al-Rabi'</a></b> was the main instigator of the <a href="./Fourth_Fitna" id="mwDLQ" rel="mw:WikiLink" title="Fourth Fitna">civil war</a> between brothers and rival <a class="mw-redirect" href="./Caliph" id="mwDLU" rel="mw:WikiLink" title="Caliph">caliphs</a> <a href="./Al-Ma'mun" id="mwDLY" rel="mw:WikiLink" title="Al-Ma'mun">al-Ma'mun</a> and <a href="./Al-Amin" id="mwDLc" rel="mw:WikiLink" title="Al-Amin">al-Amin</a>?