The Social Classes in Religious and Un-Religious texts in the Ancient Iran

In the ancient Persia, society was divided into three or four classes based on more ancient tradition. According to some scholars, this common legacy originates in the Indo-Europen period, traces of which can be found in the Indo-European societies and beliefs. It is important to find the fact that whether these classes were related to a religious belief and gods or they were brought about by a social role. What differences had the social classes in religious and non religious texts. Since most information of the classes refers to the texts in the Sasanian period, we are trying to find the division process in ancient Iran.