Kammala jumla mai zuwa: Bayan mutuwar Harun a 809, al-Abbas ya fara aiki da magajinsa al-Amin don yin aiki a matsayin manzo ga al-Ma'mun a Khurasan, amma a tsakiyar karuwar
rikici tsakanin 'yan'uwa biyu da sauri ya shawo kan sauya bangarori kuma ya ba da amincinsa ga al-Ma'mun maimakon. A watan Maris na 812 ya shiga cikin juyin mulkin da ya gaza na al-Husayn ibn Ali ibn Isa, wanda a ciki ya kasance yana da alhakin kama al-Amin da mahaifiyarsa Zubaydah bint Ja'far, kuma daga baya aka zaɓe shi ya jagoranci aikin hajji na farko da aka yi a cikin sunan al-Ma'mun, a cikin 812, 813 da 814.