In ancient Iran, mubeds were always among the most prominent authorities of the country and were highly influential in kings’ courts. This role is well depicted in Iran’s most famous national epic, and it is of such an importance that by examining their roles and positions in Shahnameh, one can find how religion and government were closely related in ancient Iran. In Shahnameh, the mubads’ responsibilities were not just limited to conducting religious ceremonies and rites. They enjoyed power and authority in country’s administration and were the most educated people of their age. They were responsible for the education and also narrated ancient stories. Observing the economic affairs and bearing the flag in battles were other responsibilities of the mubeds which are also well depicted in Shahnameh. It should be noted that “mubed” in Shahnameh is used as a generic term and it is not always used to mean a “clergy”. Rather, its meanings had expanded and the term was attributed to wise and erudite people. In this paper, the authors attempt to explain the functions and hierarchies of mubeds according to Ferdowsi’s Shahnameh.