varnas. This perspective was particularly common among scholars during the British colonial era and was articulated by Dumont, who concluded that the system was ideologically perfected several thousand years ago and has remained the primary social reality ever since. This school justifies its theory primarily by citing the ancient law book Manusmriti and disregards economic, political or historical evidence. The second school of thought focuses on socioeconomic factors and claims that those factors drive the caste system. It believes caste to be rooted in the economic, political and material history of India. This school, which is common among scholars of the post-colonial era such as Berreman, Marriott, and Dirks, describes the caste system as an ever-evolving social reality that can only be properly understood by the study of historical evidence of actual practice and the examination of verifiable circumstances in the economic, political and material history of India. This school has focused on the historical evidence from ancient and medieval society in India, during the Muslim rule between the 12th and 18th centuries, and the policies of the British colonial government from 18th century to the mid-20th century. The first school has focused on religious anthropology and disregarded other historical evidence as secondary to or derivative of this tradition. The second school has focused on sociological evidence and sought to understand the historical circumstances. The latter has criticised the former for its caste origin theory, claiming that it has dehistoricised and decontextualised Indian society. Ritual kingship model According to Samuel, referencing George L. Hart, central aspects of the later Indian caste system may originate from the ritual kingship system prior to the arrival of Brahmanism, Buddhism and Jainism in India. The system is seen in the South Indian Tamil literature from the Sangam period, dated to the third to sixth centuries CE. This theory discards the Indo-Aryan varna model as the basis of caste, and is centred on the ritual power of the king, who was "supported by a group of ritual and magical specialists of low social status," with their ritual occupations being considered 'polluted'. According to Hart, it may be this model that provided the concerns with "pollution" of the members of low status groups. The Hart model for caste origin, writes Samuel, envisions "the ancient Indian society consisting of a majority without internal caste divisions and a minority consisting of a number of small occupationally polluted groups".