The caste system in Kerala differed from that found in the rest of India. While the Indian caste system generally divided the four-fold Varna division of the society into Brahmins, Kshatriyas, Vaishyas and Shudras, in Kerala, that system was absent. The Malayali Brahmins formed the priestly class, and they considered all other castes to be either shudra or avarna (those outside the varna system). The exception to this were the military elites among the Samantha Kshatriyas and the Nairs, who were ritually promoted to the status of Kshatriya by means of the Hiranyagarbha ceremony.[1][2][3] This was done so that the Samanthans and Nairs could wield temporal ruling powers over the land, as they constituted the aristocratic class.[4][5][6] Over time, the dominance of the "upper caste" Brahmin and Nair nobles gradually declined due to social and political changes.[7][8][9]
Like the rest of India, the lower castes touching the upper castes was termed as "pollution," but only in Kerala did the lower castes pollute not just by touch but also by merely approaching an upper caste. For example, a Nair could stand next to a Namboodiri, whereas an Ezhava was forbidden to either approach or touch either the Namboodiri or the Nair.[10] In South India, only in Kerala did there appear a warrior lineage approximate to the Kshatriya model, which corresponded to the aristocratic families among the Samantan Nairs, Samantha Kshatriyas, Pillais and Kurups of travancore and the Kiryathil Nairs.[8][11][12][13][14][7]
^ abLannoy, Mark de; DeLannoy, Mark (1997). The Kulasekhara Perumals of Travancore: history and state formation in Travancore from 1671 to 1758. CNWS publications. Leiden: Research School CNWS. ISBN978-90-73782-92-1.