Investigating the religious factors of the defeat of the Sassanids against the Muslim Arabs.

In the Sassanid era, religion became the government and political and social structure was one-sided, religion was completely at the service of politics. The corrupt system of Mobdan justified the actions and behaviors of the oppressive kings, the class system and the shortcomings of the Sassanid era society. They faced a comprehensive and complete religion that emphasized equality, justice and equality. This research aims to investigate the religious factors of the defeat of the Sassanids against the Muslim Arabs with a critical approach using a descriptive-analytical method and using library sources and existing documents. Therefore, based on the results of the research, the religious factors that were effective in the defeat of the Iranians from the Arabs can be pointed to the chaotic conditions of the Sassanid era, the influence and power of the clerics or Mughans in the Sassanid era. Regarding the religion of Zoroastrianism in the Sassanid period, it should be known that this religion revolved around one axis of the Avesta book. This book was not a book containing mere religious rules, but had the status of a large encyclopedia, which included various sciences and also the clergy of the Zoroastrian religion. They were removed from the initial state. Iranshahri thought, the occurrence of wars such as Dhi Qar, religious policies of Sassanid clerics against Jews and Christians, and the emergence of Islam, are among the religious and religious factors effective in the defeat of the Sassanids from the Arabs.