Simultaneous with the arrival of Arabs, Sistan in the southeastern part of Iran although conquered, still preserved some of the pre-Islamic elements that could survive for centuries. The study and analysis of historical texts and resources reflect religious freedom among the people who had settled in Sistan for centuries. In that area, pre-Islamic Iranian beliefs such as Zoroastrianism and other religions and sects such as Christianity and Judaism were prevalent. Islam had also sects in Sistan, such as Kharijites (or the Khavarij), Karamis and Ismailis. In the meantime, the Khavarij, who were formed after the adversarial process and disintegration of the supporters of Imam Ali (PBUH) and later settled in the eastern parts of Iran due to the pressure of the Umayyads and Abbasids with branches such as Ghali Arzagheh, Atvieh, and Ajardeh, played an effective role in the survival of other religions and sects. In this research, the authors try to use the descriptive-analytical method by referring to historical sources. The goal is to give more clarity to the role of the Khawarij in the life and persistence of different religions in Sistan during the Islamic period, proving its accuracy by providing clear evidences and solid documents.
