Adi Shankaracharya

Adi Shankaracharya (788–820 CE) was the most influential philosopher in Indian history. Born in Kerala, he walked across the entire Indian subcontinent, debating and unifying Hindu philosophy under his system of Advaita Vedanta (non-dual philosophy). He established four monastic orders (mathas) at the four cardinal points of India — Sringeri (south), Dwarka (west), Puri (east), Joshimath (north) — that still function today. He wrote commentaries on the Upanishads, Brahma Sutras, and Bhagavad Gita. He died at 32, having done more in a single life than most traditions do in centuries.