- The city-state of Tahart was founded by `Abd al-Rahman Ibn Rustum, an imam of the Ibadithe sect and one of the most moderate branches of the heterodox Kharijite doctrine. From 776 to 908, the Rustumid reigned over Tahart. Welcomed by the Ibadithe communities of western Algeria, mainly Berbers of the Zanata group, Ibn Rustum rebuilt the old settlement of Tahart (near present-day Tiaret), about 225 kilometers southwest of Algiers. For over 130 years, Tahart remained the religious and intellectual focus of Kharijism in the western regions of North Africa. Tahart meant more than the spiritual leadership of a sect and of theological speculation. Tahart was also a market with a regional significance. Located in the midst of a fertile agricultural zone at the crossroads of several caravan roads, it developed a flourishing trade in the hands of a mixed population: Berbers from all over North Africa between Tripolitania and the Atlantic coast of Morocco, Arabs from every part of the east, Sunni as well as followers of various Shiite shades, and also some Christians who refused conversion to Islam.The city was destroyed under the assault of the Kutama mountain tribes led by Abu `Abd Allah al-Shi`i, the founder of the Fatimid dynasty. Consequently, a number of the inhabitants emigrated and joined the Ibadithe settlement in Sadrata near Ouargala, trying to bring Tahart back to new life there, but Sadrata, too, was conquered by the Hammadids toward the end of the 11th century. After many failed attempts, most of the people sought refuge in the desolate, stony highland of Shabka, where the Ibadithe community has survived in the Oued Mzab down to this day, known as Mozabites.
Historical Dictionary of the Berbers (Imazighen) . Hsain Ilahiane. 2014.