The metropolitan regions of the Greater Zab region in the Middle Ages, through textbooks of country geography, a historical study

the Zab is one of the most important regions in history of Maghreb, This vast geographical area, known as the province of Numidia, has witnessed historical events especially after the Islamic conquest and the calling of khawarij in region and external vocation in metropolis and cities , The province did not know the stability of capital during the Middle Ages as a result of the political situation of the country, where the capitals changed five times starting from the first capital Adhana, and tobna, msila, then the castle of Bani Hammad and finally the city of Biskra after shrinking area of the province to include the villages of Biskra only.