The Malayali Brahmins formed the priestly class, and they considered all other castes to be either shudra or avarna (those outside the varna system).
[4][5][6] Over time, the dominance of the "upper caste" Brahmin and Nair nobles gradually declined due to social and political changes.
At the time of their arrival, the non-aboriginal local population had been converted to Buddhism by missionaries who had come from the north of India and from Ceylon.
The Brahmins treated almost all of those who acceded to their priestly status as Shudra, permitting only a small number to be recognised as Kshatriya, these being some of the local rulers[which?]
By the 11th century, this combination of association with kings and invaders, and with the take-over of Buddhist temples, made the Brahmins by far the largest land-owning group in the region and they remained so until very recent times.
[16] A theory presented by Pullapilly and also by Rene Barendse, who as of 2012[update] is a Fellow of the International Institute for Asian Studies, claims that the caste system established by Nambudiri Brahmins of Kerala was in accordance with the will of Parasurama, an avatar of Vishnu.
[19] If by accident he was there and he sees an approaching Nair or a Brahmin, he must make a loud howling sound to warn the upper castes from getting near until he went away or climbed up a tree.
If a Nambudhiri Brahmin woman is accused of illegitimate sexual relations, she is kept in a separate hut as her presence could pollute other members of her family before being interrogated by a caste court, the system is known as smarttivicaram.
[24] Untouchability in Kerala is not restricted to Hindus, and George Mathew says that, "Technically, the Christians were outside the caste hierarchy, but in practice, a system of inclusion and exclusion was developed ...".
[26][30] Rajendra Prasad, an Indian historian, said that the Syrian Christians took ritual baths after physical contact with lower castes .
The rules of untouchability were severe, and they were very strictly enforced among Hindu communities by the time of the arrival of the Dutch East India Company in the 17th century.
[17] Robin Jeffrey, who is a professor specialising in the modern history and politics of India, quotes the wife of a Christian missionary, who wrote in 1860 that: ... a Nair can approach but not touch a Namboodiri Brahmin: a Ezhava must remain thirty-six paces off, and a Pulayan slave ninety-six steps distant.
There were also responsibilities to protect such people from the dangers of attack and other threats to their livelihood, and so it has been described by Barendse as "an intricate dialectic of rights and duties".
[32] According to an estimate by Dr. Francis Buchanan in 1801 AD, 41,367 persons out of the 292,366 populations were slaves in the south, central and Northern divisions of the Malabar.
By the late 19th century, the caste system of Kerala had evolved to be the most complex to be found anywhere in India,[36] and the exploitation of it had become considerable.
Barendse explains this development: ... it turned to gross unrequited exploitation only in the nineteenth century when the British colonial pacification removed the threat of the peasant harvests being ravaged by armies or robbers and their huts being burned to the ground.
[37]By this time there were over 500 groups represented in an elaborate structure of relationships and the concept of ritual pollution extended not merely to untouchability but even further, to un-approachability and even un-seeability.
The roles left empty by the absence of these ritual ranks were taken to some extent by Nairs, Mappila Muslims and Syrian Christians.
[39]Despite being outlawed, the Indian governments – both at national and at regional level – do still recognise distinctions between the various communities but this recognition is for the purpose of positive discrimination.
Throughout post-independence India, including in Kerala, there exists a framework of reservation which is fluid in nature and attempts to recognise the socio-economic disparities between various castes.
The safeguards enshrined in the Constitution stipulate that governments should take special care to advance the educational and economic interests of Scheduled Castes, that untouchability is unacceptable and that all Dalit communities should have unrestricted entry in Hindu temples and other religious institutions.