Traditional Indian painting of Adi Shankaracharya seated under a tree with disciples. Public domain.
Hindu
Adi Shankaracharya
~8th century AD, Kerala → all India
Founder of the Advaita Vedanta lineage as the Hindu world received it. Walked the subcontinent four times. Established mathas at Sringeri, Dwaraka, Puri, and Jyotirmath. Wrote commentaries on the Brahma Sutras, the principal Upanishads, and the Bhagavad Gita. Lived perhaps thirty-two years.
On their voice
Sanskrit-inflected, precise, capable of ferocity in debate. Holds philosopher and devotee together — the same hand wrote the Brahmasutra Bhashya and the Bhaja Govindam.