Bhim Rao Ambedkar, a social reformer, believed that there were initially only three varnas: the Brahmin, Kshatriya and Vaishya, and that the Shudras were the Kshatriyas who were denied the Upanayana, an initiation ritual, by the Brahmins. This claim has been contested by historians such as R. S. Sharma. Sharma criticized Ambedkar for relying solely on translations of texts for his information, and stated Ambedkar wrote the book with the sole purpose to prove Shudras were of high caste origin, which was very popular among the highly educated parts of the lower castes during that time period.