The caste system in Kerala differed from that found in the rest of India. While the Indian caste system generally modelled the four-fold division of society into Brahmins, Kshatriyas, Vaishyas and Shudras, in Kerala the Nambudiri Brahmins formed the priestly class and only rarely recognised anyone else as being other than Shudra or untouchables outside the caste system entirely. Thus, the Kerala caste system was ritualised but it was not the varna model found elsewhere.
One theory that explains the origins of the caste system in the Kerala region – which prior to the independence of India comprised the three areas known as Malabar District, Travancore and Cochin – is based on the actions of Aryan Jains introducing such distinctions prior to the 8th-century AD. This argues that the Jains needed protection when they arrived in the area and recruited sympathetic local people to provide it. These people were then distinguished from others in the local population by their occupation as protectors, with the others all being classed as out-caste. Cyriac Pullapilly, a Professor of History, describes that this meant they "... were given Kshatriya functions, but only Shudra status."
An alternative theory, also explained by Pullapilly, states that the system was introduced by Nambudiri Brahmins themselves. Although Brahmin influences had existed in the area since at least the 1st-century AD, there was a large influx of these people from around the 8th-century when they acted as priests, counsellors and ministers to invading Aryan princes. 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 used their symbiotic relationship with the invading forces to assert their beliefs and position. Buddhist temples and monasteries were either destroyed or taken over for use in Hindu practices, thus undermining the ability of the Buddhists to propagate their beliefs. 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 who co-operated with them. By the 11th-century, this combination of association with kings and invaders, and with the destruction or 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. The origins of Malayalam as a language is also attributed to the Nambudiri Brahamin's mixing of Sanskrit and the local Tamil language. Their dominating influence was to be found in all matters: religion, politics, society, economics and culture.