The Samanid state was founded by four brothers; Nuh, Ahmad, Yahya, and Ilyas—each of them ruled their own territory under Abbasid suzerainty. In 892, Isma'il ibn Ahmad (892–907) united the Samanid state under one ruler, thus effectively putting an end to the feudal system used by the Samanids. It was also under him that the Samanids became independent of Abbasid authority.
The Samanid Empire is part of the Iranian Intermezzo, which saw the creation of a Persianate culture and identity that brought Iranian speech and traditions into the fold of the Islamic world. This would lead to the formation of the Turko-Persian culture.
The Samanids promoted the arts, giving rise to the advancement of science and literature, and thus attracted scholars such as Rudaki, Ferdowsi, and Avicenna. While under Samanid control, Bukhara was a rival to Baghdad in its glory. Scholars note that the Samanids revived Persian more than the Buyids and the Saffarids, while continuing to patronize Arabic to a smaller degree. In a famous edict, Samanid authorities declared that "here, in this region, the language is Persian, and the kings of this realm are Persian kings."
The eponymous ancestor of the Samanid dynasty was Saman Khuda, a Persian noble who belonged to a dehqan family, which was a class of land-owning magnates. The original home of the Samanids is unclear, for some Arabic and Persian texts claim that the name was derived from a village near Samarkand, while others assert it was a village near Balkh or Tirmidh. The latter is more probable since the earliest appearance of the Samanid family appears to be in Khorasan rather than Transoxiana. In some sources the Samanids claimed to be descended from the noble Mihran family of Bahram Chobin, whereas one author claimed that they belonged to the Turkish Oghuz tribe, although this is most unlikely. Originally a Zoroastrian, Saman Khuda converted to Islam during the governorship of Asad ibn Abdallah al-Qasri in Khorasan, and named his oldest son as Asad in the governor's honour. In 819, the governor of Khorasan, Ghassan ibn Abbad, rewarded the four sons of Asad for their aid against the rebel Rafi ibn al-Layth; Nuh received Samarkand; Ahmad received Farghana; Yahya received Shash; and Ilyas received Herat. This marked the beginning of the Samanid dynasty.
Ilyas died in 856, and was succeeded by his son Ibrahim ibn Ilyas—the Tahirid governor of Khorasan, Muhammad ibn Tahir, thereafter appointed him as the commander of his army, and sent him on an expedition against the Saffarid ruler Ya'qub ibn al-Layth al-Saffar in Sistan. He was defeated at a battle near Pushang in 857, and fled to Nishapur, where he was captured by Ya'qub al-Saffar and sent to Sistan as a hostage. The Tahirids thereafter assumed direct control over Herat.