Nārāyana Guru (नारायण गुरु,നാരായണ ഗുരു) (1855 - 1928), also known as Sree Nārāyana Guru Swami, was a saint, sage and social reformer of India. The Guru was born into an Ezhava family, in an era when people from backward communities like the Ezhavas faced much social injustices in the caste-ridden Kerala society. Gurudevan, as he was fondly known to his followers, revolted against casteism and worked on propagating new values of freedom in spirituality and of social equality, thereby transforming the Kerala society; as such he is adored as a prophet.[1][2]

Nārāyana Guru is revered for his Vedic knowledge, poetic proficiency, openness to the views of others, non-violent philosophy and his unrelenting resolve to set aright social wrongs. Nārāyana Guru was instrumental in setting the spiritual foundations for social reform[3] in today's Kerala and was one of the most successful social reformers who tackled caste in India. He demonstrated a path to social emancipation without invoking the dualism of the oppressed and the oppressor.

Guru stressed the need for the spiritual and social upliftment of the downtrodden by their own efforts through the establishment of temples and educational institutions. In the process he brushed aside the Hindu religious conventions based upon Chaturvarna. His transformation of the social face of Kerala relied on emphasizing, yet re-evaluating, the Advaita philosophy of Adi Sankaracharya.

More info at http://en.wikipedia.org/wiki/Narayana_Guru