Sistan became a province of the Umayyad and Abbasid Caliphates. The Abbasid dynasty rose to power in 750, consolidating the gains of the earlier Caliphates. The Rajputs held out against the Caliphates and Central Asian empires for several centuries. In post-classical history, the Arab world was synonymous with the historic Arab empires and caliphates. Since the Umayyads, all Caliphates have been dynastic. Changes soon eroded the established tax base of the early Arab Caliphates. During the early caliphates, Manichaeism attracted many followers. "Caliphates not accepted as legitimate by the majority of Muslims". This type of behavior was utterly unprecedented in previous Muslim caliphates. Unfortunately, this has led to the systematic persecution of Baha'is by many caliphates.