The chief social unit of the Aryans was known as jana.
The chief of this unit was the political leader called rajan.
The main function of the chief was to protect the jana and cattle from the enemies. He was helped in his task by the tribal assemblies called sabha, samiti, vidatha, gana and parishad.
Out of these sabha and samiti were the most important assemblies.
Women were allowed to participate in the deliberations of the sabha and samiti.
The post of the chief was not hereditary.
The tribe generally elected him.
Though the succession in one family was known but that was not based on the rule of primogeniture (i.e., the eldest son acquiring the position).
The purohita assisted and advised the chief on various matters.
Other than the purohita, there were a limited number of other officials who assisted the chief in the day-to-day tribal affairs. Senani, kulapa, gramani, etc. are some of the functionaries.
The early Vedic polity was an uncomplicated system based on the support and active participation of all the tribesmen.
The changes in the material and social life during the later Vedic period led to changes in the political sphere as well.
The nature of chiefship changed in this period.
The territorial idea gained ground.
The people started to loose their control over the chief and the popular assemblies gradually disappeared.
The post of chief became hereditary.
The elaborate coronation rituals such as vajapeya and rajasuya established the chief authority.
The officers were appointed to help the chief in administration and they acquired the functions of the popular assemblies as main advisors.
A rudimentary army emerged as an important element of the political structure during this period.
All these lived on the taxes called bali, the shulka, and the bhaga offered by the people.
The chiefs of this period belonged to the kshatriya varna and they in league with the brahmanas tried to establish complete control over the people in the name of dharma.