The Varna system in the Vedic age was based on one’s work or duty (Karma). Members of a family used to engage themselves in different types of work (profession) and their work decided their Varna.
During the Vedic period one could choose a particular profession as he liked and accordingly his Varna was determined.
But during the Post-Vedic period Varna came to be determined by birth. Consequently, the whole society was divided into four Varnas- Brahman, Kshatriya, Vaishya and Shudra.
Out of these four Vamas, the Brahmans occupied the supreme position and enjoyed more rights. Kshatriyas resented this superiority and a clash ensued between the two. Kshatriya was the winners in the clash and the administrative powers came into their hands. Gradually they established their kingdoms and principalities.
Thus in the Varna system the Brahmans and the Kshatriyas became predominant. The Vaishyas and Shudras came into the lower groups. In this hierarchy Shudras were kept at the lowest order of society.
In course of time the condition of Shudras fell down further and they came to be regarded as untouchables and they were denied all social and religious rights.
Vaishyas remained superior to Shudras and they divided themselves into professional groups such as-goldsmith, blacksmith, potter, fowler, milkman and sweet-seller etc., etc.
However, the position of Varnas during the Post-Vedic period had not degenerated so much as it is found today. Then, it was possible to change one’s Varma. One could marry a girl from a different Varna.
The Vaishyas were permitted in the Rajya Surya Yajna upto some extent. Then, Brahmans also did not control the Yajnas. The marriages of Chyavan Rishi and king Shantanu and the religious rites performed by Vishwamitra (A Kshatriya) and other Kshatriyas bear a testimony to the above.
The Post-Vedic literature does not contain much about the education of Vaishyas and Shudras. Agriculture was the main occupation of Vaishyas during this period.
Shudras were given education by Brahmans. But the number of educated Shudras fell down day by day. According to Shatpaths, fisherman, snake-charmers and other alike professionals were some of the other students of Brahmans. Shudras were mostly engaged in manual labour in agricultural fields, grazing cattle and pottery. Some of them knew music and dance as well as we find even today.