This research aims to elucidate the moment of administrative law's genesis in Iran by phenomenologically analyzing the transition from the institution of the Divan to the construct of the Idareh (modern administration). Prior to the Constitutional Revolution in Iran, the Divan was not structured on the basis of modern formal rationality and bureaucracy. Instead, it was organized around royal justice and personal authority. The Divan was a historical-cultural system that evolved in Iran, aligning with the spirit and demands of the Iranian people. Its functionaries were not expert specialists or managers but rather literati and scholars who developed within the Iranian context and its culture, educated according to a specific Iranian worldview. This explains why most members of the Iranian Divan were also poets, men of letters, astronomers, and philosophers. They served the Divan based on the ideals in which they were raised. The Shah presided over this Divan, and everyone obeyed him, with justice forming its foundation. The Divan lacked the fundamental characteristics of modern bureaucracy, including a systematic hierarchical structure, separation of workplace from personal life, precise legal competencies, and a coherent system of administrative duties and offices. Furthermore, the Divan's value-laden foundation, rooted in the ideal of substantive justice, differentiated it from bureaucracy, which is a calculable and non-value-driven system. However, in the contemporary era, Malcom Khan, with his profound understanding of the logic of legal administration in Europe, expounded upon the components of bureaucracy in his works to establish a model for creating the Idareh. He laid the first theoretical groundwork for administrative law in Iran. Subsequently, the practical transition to modern administration began with the Sepahsalar's reforms and was solidified during the Constitutional Revolution. This process involved the transformation of the Divan's personal and traditional offices into legal and specialized administrative structures. Consequently, administrative law in Iran was not a continuation of the Divan but rather the outcome of moving beyond it and establishing modern rationality. Thus, the founding moment of administrative law was a break from the past and an embrace of a new conceptual framework that carried within it the exigencies of the modern phenomenon: the modern administrative system and, by extension, modern administrative law with its specific demands and characteristics. Therefore, any understanding or theory of administrative law in Iran must be based on a precise distinction and differentiation between the Divan and the Idareh.