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. 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: Nonetheless, higher ranked communities did have some social responsibility for those perceived to be their inferiors: for example, they could demand forced labor but had to provide food for such laborers, and they had responsibilities in times of famine to provide their tenants both with food and with the seeds to grow it. 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". Ritual pollution during slavery 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. In the census of 1836, 164,864 people out of the 1,280,668 were slaves in Travancore. There was an estimated 4.25 lakh slaves in Kerala during the middle of the 19th century. The slaves belonged to the lower castes and were employed only for feudal work, and the stigma that they should be kept away from their masters was strictly followed. Samuel Mateer, noted that even in the working fields the slaves were supervised from a distance. Based on the 1881 census an estimated 40,000 slaves converted to Islam from 1871 to 1881. Many slaves also converted to Christianity in Cochin and Travancore during this period. During the 1882 Christian Mission Conference, it was reported that the population of Muslim Mapillas were increasing rapidly due to the conversion from the lower strata of the Hindu society, and that the entire west coast could become Muslim. Caste system in colonial Kerala By the late 19th century, the caste system of Kerala had evolved to be the most complex to be found anywhere in India, and the exploitation of it had become considerable. Barendse explains this development: By this time there were over 500 groups represented in an elaborate structure of relationships and the concept