The earliest Aryan divisions of society were apparently marked by occupations. At first there were three grades: warriors, priests, and traders, but all classes might engage in agricultural pursuits; even in the Epic period princes counted and branded cattle. In the later Vedic age, however, a rigid system of castes came into existence, the result, apparently, of having to distinguish between Aryans and aborigines at first, and subsequently between the various degrees of Aryans who had intermarried with aliens. Caste (Varna) signifies colour, and its relation to occupation is apparent in the four divisions—Brahmans, priests; Kshatriyas, the military aristocracy; Vaisyas, commoners, workers, and traders, who were freemen; and Sudras, slaves and aborigines. In the _Yajurveda_, the third Veda, the caste system is found established on a hereditary basis. The three upper castes, which were composed of Aryans only, partook in all religious ceremonials, but the members of the Sudra caste were hedged about by severe restrictions. The knowledge of the Vedas was denied to them, and they were not allowed to partake of Soma offerings, and although in the process of time their position improved somewhat in the religious life of the mingled people, their social inferiority was ever emphasized; they might become traders, but never Kshatriyas or Brahmans. The most renowned of early Brahmans were the Rishis, the poets[129] who composed the “new songs” to the gods. They were regarded as divinely inspired men and their fame was perpetuated after death. Several renowned poets are referred to in sacred literature and invested with great sanctity. The hymns or mantras were committed to memory and then handed down from generation to generation. At religious ceremonies these were chanted by reciters, the Hotri priests. There were also priests who were skilled in the correct performance of sacrificial rites, and family priests, the Purohitas, who were the guides, philosophers, and friends of kings and noblemen. A Rishi might be a Purohita and a seer, who ensured by the performance of mystic ceremonies a monarch's success in battle and afterwards celebrated his achievements in song. [129] “A Rishi, ‘seer’, is primarily a composer of hymns.... The Rishis ultimately become the representatives of a sacred past.” _Vedic Index of Names and Subjects_ vol. i, pp. 115-117 (1912). In the process of time an organized priesthood came into existence, and a clan or kingdom had its chief priest. The production of new hymns came to an end; those which existed were considered sufficient for all purposes; religious beliefs were systematized, and an arbitrary ritual became more and more complicated.