Abstract
The Sassanian Empire, on one hand, claimed the religious legacy of Zoroastrianism, and on the other hand, was in constant conflict with a powerful rival, the Roman Empire, over hegemony in the ancient world. Therefore, it followed a specific model for the relationship between religion and politics to address its needs and circumstances. This article explores aspects of this relationship by posing the central question of the connection between religion and politics in the Sassanian era. The hypothesis of the article is that every model of power is connected to a system of beliefs that provides its explanatory and justifying foundations. Research findings indicate that the unity of religion and politics was a key component of the Sassanian ideological system, which can explain many historical events of this period. The article uses Foucault's discourse analysis method, and the data collection approach is library-based and documentary.
Keywords: Religion and state, Foucault, Discourse, Knowledge, Power.
 
Introduction
The Sassanian Empire inherited two major legacies: religiously, it regarded itself as the guardian of Zoroastrianism, and politically, it sought to restore Iran's unquestioned authority in the ancient world. These dual inheritances necessitated the design of a particular model for the relationship between religion and politics. Consequently, Zoroastrianism was adopted as the official religion of the empire. However, the union or connection between religion and politics does not necessarily mean the creation of a theocratic government but can be understood as the idea that any form of power requires a system of beliefs to justify and explain its moral and civil legitimacy. This interaction between religion and politics could also be influential in shaping national identity, making it central to understanding the Sassanian Empire's political-religious system.
 
Materials & Methods
For power to sustain itself, it must create a "regime of truth." In other words, no relationship of power exists without the formation of a body of knowledge, and no knowledge exists without underlying power relations. Foucault analyzes power not in its classical form, but as a network of horizontal relations. He examines discourses based on their relationship to knowledge and power. For Foucault, power and knowledge become unified within discourse. Each form of power produces its own epistemic model, with power shaping knowledge and knowledge promoting what power desires as "truth." A power system also has its own system of knowledge, which collectively provides the rules for controlling society and managing individuals. The unity of power and knowledge is manifested in discourse, and by analyzing discourse, we can understand the relationships of power and knowledge in any society.
 
Discussion & Result:
During the Sassanian period, political and religious discourses were deeply intertwined, with a close relationship between the monarchy and the clergy. Religion and politics were not only side by side but were mutually dependent. The king and the Zoroastrian clergy worked together to preserve and promote both religion and governance. Various texts, especially from the "Era of Ardashir," highlight that religion and governance were like two inseparable brothers, unable to exist without each other. This connection represents the deep and complex relationship between religion and governance in the Sassanian era, functioning as a dual relationship rather than a theocracy.  During the reigns of Ardashir and Shapur I, the Sassanian government strongly supported Zoroastrianism, deriving its legitimacy from the divine "farrah" (royal grace) and backing for the Zoroastrian faith. At the empire's borders, it tolerated religious diversity, but within its core territories, it harshly dealt with heresy and religious change. This dual policy led to contradictions in dealing with other religions and dissenters. The Sassanian discourse, especially in its official theories and practices, emphasized the unity of religion and kingship. The kings, in their decrees and advice, asserted that both monarchy and religion were inseparable components of society, helping to maintain power and social order. In practice, supporting the Zoroastrian clergy and controlling society through religion, particularly in social and political matters, were daily aspects of government policy. This close relationship between religion and state played an important role in creating social order and stability.
 
Conclusion
The Sassanian Empire's legacy significantly influenced the development of early Islamic traditions and institutions. The Sassanids used the political-religious discourse of "religion and kingship" to justify their authority, suppressing any resistance, religious conversion, or dissent by labeling opponents as "heretics" or "innovators." Through their exclusive interpretation of religious texts, they suppressed any counter-discourses or alternative views to preserve their power.