Sa'id was a son of Caliph Uthman (r. 644–656) and the latter's wife Fatima bint al-Walid, a scion of the prominent Banu Makhzum clan of the Quraysh.
[2] Upon hearing news that he had nominated his son Yazid I (r. 680–683) as his successor, Sa'id left Medina for Mu'awiya's court in Damascus to petition against the decision.
Though there were capable commanders among the men assigned to Sa'id, including al-Muhallab ibn Abi Sufra, many of the troops collected were Basran prisoners and otherwise disruptive tribal elements from the population.
[9] Mu'awiya restricted Sa'id's jurisdiction to military affairs, assigning fiscal responsibilities to Ishaq ibn Talha, who died en route to Khurasan and was replaced in the role by Aslam ibn Zur'a al-Kilabi, a Qaysite tribal leader in the Khurasan garrison and the province's former lieutenant governor.
[10] According to the historian Muhammad Shaban, Mu'awiya's deployment of Sa'id and Ishaq represented efforts to ensure that the surplus tax revenue of Khurasan, in addition to the traditional fifth of the war booty from the conquests there, was forwarded to the caliphal treasury in Damascus.
This was generally opposed by the Arab tribesmen who made up the ranks of Khurasan's garrisons, who sought to keep the bulk of the provincial revenue under their control.
[13] Al-Baladhuri and Narshakhi hold that Sa'id's crossing of the Oxus prompted Khatun, the queen of Bukhara to give allegiance to the Caliphate, but she then reneged upon the arrival of a supportive 120,000-strong army of Turks, Soghdians and soldiers from Kish and Nasaf.
[6] Sa'id had at least two wives, one of whom was Ramla, the daughter of Mu'awiya's father and a leading figure among the Quraysh, Abu Sufyan ibn Harb; the other wife is not named in the sources.