(1) One of the greatest philosophers of India, Adi Shankaracharya founded the Advaita Vedanta, which is one of the sub-schools of Vedanta. Adi Shankaracharya whole-heartedly believed in the concept of the Vedas but at the same time advocated against the rituals and religious practices that were over exaggerated. He established four spiritual centres in the four corners of the country,thus upholding the underlying unity of the holy land of Bharat. Ramanujacharya Chief exponent of the Vishi-shtadvaita school of Vedanta and a great social reformer. He established the Yatiraja Math and the Cheluvanarayana-swami temple at Melkote in Karnataka, and also renovated many ancient temples. He wrote many philosophical works and preached the oneness of mankind. Chaitanya Mahaprabhu was a spiritual leader who founded Gaudiya Vaishnavism. He is believed by his devotees to be Krishna himself. Chaitanya was the proponent for the Vaishnava school of Bhakti yoga (meaning loving devotion to God),based on Bhagavata Purana and Bhagavad Gita. He composed the Siksastakam (eight devotional prayers) in Sanskrit.