Editing Al-Mu'tasim (section)

===Activity during the civil war===
[[File:Coin of the Abbasid Caliph al-Ma'mun.jpg|thumb|upright=1.2|alt=Obverse and reverse of gold coin with Arabic inscriptions|A gold dinar of al-Ma'mun, minted in Egypt in 830/1]]
As one of Harun's younger sons, Abu Ishaq was initially of little consequence, and did not figure in the line of succession.{{sfn|Kennedy|2006|p=213}} Soon after Harun died in 809, a [[Fourth Fitna|vicious civil war]] broke out between his elder half-brothers [[al-Amin]] ({{reign|809|813}}) and [[al-Ma'mun]] ({{reign|813|833}}). Al-Amin enjoyed the backing of the traditional Abbasid elites in Baghdad (the ''[[abna al-dawla|abnāʾ al-dawla]]''), while al-Ma'mun was supported by other sections of the ''abnāʾ''. Al-Ma'mun emerged victorious in 813 with the surrender of Baghdad after a [[Siege of Baghdad (812–813)|long siege]] and the death of al-Amin.{{sfn|Kennedy|2004a|pp=147–151}}{{sfn|Gordon|2001|pp=27–28}} Choosing to remain in his stronghold in [[Khurasan]], on the northeastern periphery of the Islamic world, al-Ma'mun allowed his main lieutenants to rule in his stead in Iraq. This resulted in a wave of antipathy towards al-Ma'mun and his "Persian" lieutenants, both among the Abbasid elites in Baghdad and generally in the western regions of the Caliphate, culminating in the nomination of Harun al-Rashid's younger brother [[Ibrahim ibn al-Mahdi|Ibrahim]] as anti-caliph at Baghdad in 817. This event made al-Ma'mun realise his inability to rule from afar; bowing to popular reaction, he dismissed or executed his closest lieutenants, and returned in person to Baghdad in 819 to begin the difficult task of rebuilding the state.{{sfn|Kennedy|2004a|pp=151–153}}{{sfn|Gordon|2001|pp=28–29}}

Throughout the conflict and its aftermath, Abu Ishaq remained in Baghdad.{{sfn|Kennedy|2004a|p=156}}{{sfn|Gordon|2001|p=25}} Al-Tabari records that Abu Ishaq led the [[Hajj]] pilgrimage in 816, accompanied by many troops and officials, among whom was [[Hamdawayh ibn Ali ibn Isa ibn Mahan]], who had just been appointed to the governorship of the [[Yemen]] and was on his way there. During his stay in Mecca, his troops defeated and captured a pro-[[Alid]]{{efn|The relationship between the Abbasids and the Alids was troubled and underwent many changes. The Alids, claiming descent from [[Muhammad]]'s son-in-law [[Ali]], had been the focal point of several failed revolts directed against the [[Umayyad Caliphate|Umayyads]]—whose regime was widely regarded as oppressive and more concerned with the worldly aspects of the caliphate than the teachings of Islam—inspired by the belief that only a "chosen one from the Family of Muhammad" (''al-riḍā min Āl Muḥammad'') would have the divine guidance necessary to rule according to the [[Quran]] and the [[Sunnah]] and create a truly Islamic government that would bring justice to the Muslim community. However, it was the Abbasid family, who like the Alids formed part of the [[Banu Hashim]] clan and hence were members of the wider "Family of the Prophet", who seized the Caliphate in the [[Abbasid Revolution]].{{sfn|Kennedy|2004a|pp=123–127}}{{sfn|El-Hibri|2010|pp=269–271}} In its aftermath, the Abbasids tried to secure Alid support or at least acquiescence through salaries and honours at court, but some, chiefly the [[Zaydi]] and [[Hasan ibn Ali|Hasanid]] branches of the Alids, continued to reject the Abbasids as usurpers. Thereafter, periods of conciliatory efforts alternated with periods of suppression by the caliphs, provoking Alid uprisings which were followed in turn by large-scale persecutions of the Alids and their supporters.{{sfn|Kennedy|2004a|pp=130–131, 136, 139, 141}}{{sfn|El-Hibri|2010|p=272}}}} leader who had raided the pilgrim caravans.{{sfn|Bosworth|1987|pp=37–39}} He also led the pilgrimage the following year, but no details are known.{{sfn|Bosworth|1987|p=45}} It appears that at least during this time, Abu Ishaq was loyal to al-Ma'mun and his viceroy in Iraq, [[al-Hasan ibn Sahl]],{{sfn|Gordon|2001|p=25}} but, like most members of the dynasty and the ''abnāʾ'' of Baghdad, he supported his half-uncle Ibrahim against al-Ma'mun in 817–819.{{sfn|Kennedy|2004a|p=156}}