In around 204/ 819, the Abbasid Caliph al-Ma ʾmūn (r. 198–218/ 813–33), through his governor in Khurasan, Ghassān b. ʿAbbād (202–5/ 817–20), appointed four Samanid brothers, sons of Asad b. Sāmānkhudā, to the governorships of the four principal towns of Transoxiana, Bukhara, Samarqand, Shash and Farghana, and inaugurated the era of Samanid dynastic rule (204– 395/ 819–1005). The Samanids had successfully assisted al-Ma ʿmūn in the caliphate's efforts to suppress the revolt of Rāfiʿ b. al-Layth, who in 190/ 806 had initiated in Samarqand a rebellion that spread across Transoxiana and attracted the involvement of surrounding peoples and regions. After Ghassān's dismissal in 205/ 821 and the appointment in the same year of al-Ma ʾmūn's commander ʺāhir b. al-Óusayn (159–207/ 776–822) as Amir of Khurasan, the Samanids retained their posts and their strength in Transoxiana grew steadily during the ensuing period of the Tahirids’ governance in Khurasan.

Information regarding the earlier history of the Samanid family is sparse but suggestive. Of particular interest is the Samanids’ claim, widely accepted among their contemporaries and later commentators, to an ancestral lineage from the general Bahrām-i Chūbīn. A scion of the Arsacid (Parthian) family of Mihrān, one of the great families of late antique Iran, Bahrām, probably born in Rayy, led a major rebellion in 590–1 against the Sasanian monarchs Hurmuzd IV (r. 579–90) and Khusraw II (r. 590–628). His challenge to the legitimacy of Sasanian rule found strong support in the formerly Parthian domains of the northern and eastern regions of the Iranian cultural world, where Sasanian power had always been tenuous. It was in these regions that, some three centuries later, the Samanids rose to power; their long-standing rivals the Buyids (320–454/ 932–1062) held the heartlands of the former Sasanian Empire in western Iran and Iraq. The Samanids’ association with Bahrām-i Chūbīn strengthened their ancestral claims to the eastern regions, where, according to the pre-eminent geographers of the middle decades of the tenth century, al-Iṣṭakhrī and Ibn Óawqal, Bahrām-i Chūbīn's ‘reputation among the Persians for strength and courage has remained current’ (sāra dhikruhu fī l- ʿajam bi-l- ba ʾs wa-l- najda).