Adi Shankara, also known as Shankaracharya, was an influential Indian philosopher and theologian who lived in the early 8th century CE. He is best known for consolidating the doctrine of Advaita Vedanta, which emphasizes non-dualism and the idea that the individual soul (Atman) is identical to the ultimate reality (Brahman). His teachings have had a profound impact on Hindu philosophy and spirituality. Shankara traveled extensively across India, establishing four major monasteries, known as mathas, to promote his teachings. He wrote numerous texts, including commentaries on the Upanishads, Bhagavad Gita, and Brahma Sutras, which continue to be studied and revered today. His work laid the foundation for later developments in Hindu thought and practice.