Tiaret had grown up as a site under the domination of petty Berber tribal kingdoms; the first of these being the Rustamid dynasty between 761 and 909 when Tiaret serves as the capital of the area.
However, this capital may have been ten kilometers (six or seven miles) west of the present-day Tiaret.
It was first founded by Abd al-Rahman Rustamid, an Ibadi theologian from Greater Iran.
Tiaret was said to be relatively freethinking and democratic, being a center for scholarship that permits a wide range of sects and movements, notably the Mu'tazila.
There are many Jews living in the area until at least the tenth century, including the scholar and doctor Judah ibn Kuraish, who becomes the doctor to the Emir of Fes.
Tiaret occupies a strategic mountain pass at 3,552 feet (1,083 meters), and is thus a key to dominating the central Maghreb.
Later, from the start of the eighth century, it has served the key northern terminus of the West African branch of the slave trade.
As such, it offers a lucrative income from taxes on the trade, and is a desirable prize.
The Rustamids had fought the Kairouan-based Aghlabids of Ifriqiya in 812, but have otherwise reached a modus vivendi; this had displeased Ibādī tribes on the Aghlabid border, who have launched a few rebellions.
After Abdu l-Wahhāb, the Rustamids had grown militarily weak; they are easily conquered by the Berber Kutama tribesmen, allied to the Ismaili Fatimids, in 909, upon which many Ibāḍis—including the last Imām—flee their capital to the Sedrata tribe of Ouargla, whence they will ultimately emigrate to Mzab.