Adi Shankaracharya — The Renovator of Vedanta
Adi Shankaracharya (788-820 CE) is the greatest systematizer of Advaita Vedanta — who at 32 years of age had written commentaries on all major Upanishads, the Brahmasutras, and the Bhagavad Gita, and revived Vedic Hinduism.
Adi Shankaracharya (Shankara — 'bestowing happiness') is arguably the greatest philosophical genius in Indian history. Born in Kerala at approximately 788 CE, he is traditionally said to have lived only 32 years — yet in that time wrote comprehensive commentaries on the ten major Upanishads, the Brahmasutras (Shariraka Mimamsa Bhashya), and the Bhagavad Gita; composed devotional hymns (stotras) of great beauty; founded four Mathas (monastic centers) at the four corners of India (Sringeri, Dwarka, Puri, Badrinath); and engaged in public debates (shastrarthas) with rival philosophical schools (including Buddhist, Sankhya, Mimamsa, and Nyaya) in which he is said to have been universally victorious. His philosophical achievement: a systematic, non-dualistic reading of the entire Vedic corpus that positioned Brahman-Atman identity as the highest truth, against the Buddhist schools on one side and the dualistic Hindu schools on the other. No thinker before or since has compressed so much philosophical achievement into so short a life.
There is Brahman only, one, without a second. There is no multiplicity. Brahman is the one reality.
Philosopher Karl Jaspers included Shankara among the 'great philosophers' of humanity alongside Socrates, Confucius, and Buddha — recognizing that Shankara's systematic non-dualism represents one of the most rigorous and comprehensive philosophical achievements in any tradition.
Brahmasutra Bhashya