"sruthi smruthi puraananaam aalayam karunaalayam namaami bagavathpatha sankaram loka sankaram"

Adi Shankara or Shankara, was an early Indian philosopher and theologian who consolidated the doctrine of Advaita Vedanta. He is credited with unifying and establishing the main currents of thought in Hinduism.

His works in Sanskrit discuss the unity of the athma and Nirguna Brahmam "brahmam without attributes". He wrote copious commentaries on the Vedic canon Brahma Sutras, Principal Upanishads and Bhagavad Gita in support of his thesis. His works elaborate on ideas found in the Upanishads. Shankara's publications criticised the ritually-oriented Mimamsa school of Hinduism. He also explained the key difference between Hinduism and Buddhism, stating that Hinduism asserts "Athma (Soul, Self) exists", while Buddhism asserts that there is "no Soul, no Self".

Shankara travelled across the Indian subcontinent to propagate his philosophy through discourses and debates with other thinkers. He established the importance of monastic life as sanctioned in the Upanishads and Brahma Sutra, in a time when the Mimamsa school established strict ritualism and ridiculed monasticism. He is reputed to have founded four mutts ("monasteries"), which helped in the historical development, revival and spread of Advaita Vedanta of which he is known as the greatest revivalist. Adi Shankara is believed to be the organiser of the Dashanami monastic order and unified the Shanmata tradition of worship. He is also known as Adi Shankaracharya, Shankara Bhagavatpada, sometimes spelled as Sankaracharya, (Adi) SankaracharyaSankara Bhagavatpadha and Sankara Bhagavatpadhacharya.

LIFE

Shankara was born in the southern Indian state of Kerala, in a village named Kaladi.  

Shankara's hagiography describe him as someone who was attracted to the life of Sanyasa (hermit) from early childhood. His mother disapproved. A story, found in all hagiographies, describe Shankara at age eight going to a river with his mother to bathe, and where he is caught by a crocodile. Shankara called out to his mother to give him permission to become a Sannyasin or else the crocodile will kill him. The mother agrees, Shankara is freed and leaves his home for education. He reaches a Saivite sanctuary along a river in a north-central state of India, and becomes the disciple of a teacher named Govinda Bhagavatpada. The stories in various hagiographies diverge in details about the first meeting between Shankara and his Guru, where they met, as well as what happened later. Several texts suggest Shankara schooling with Govindapada happened along the river Narmada in Omkareshwar, a few place it along river Ganges in Kashi (Varanasi) as well as Badari (Badrinath in the Himalayas).

The biographies vary in their description of where he went, who he met and debated and many other details of his life. Most mention Shankara studying the Vedas, Upanishads and Brahmasutra with Govindapada, and Shankara authoring several key works in his youth, while he was studying with his teacher. It is with his teacher Govinda, that Shankara studied Gaudapadiya Karika, as Govinda was himself taught by Gaudapada.  Most also mention a meeting with scholars of the Mimamsa school of Hinduism namely Kumarila and Prabhakara, as well as Mandana and various Buddhists, in Shastrarth (an Indian tradition of public philosophical debates attended by large number of people, sometimes with royalty).  Thereafter, the biographies about Shankara vary significantly. Different and widely inconsistent accounts of his life include diverse journeys, pilgrimages, public debates, installation of yantras and lingas, as well as the founding of monastic centers in north, east, west and south India.

Philosophical tour and disciples

While the details and chronology vary, most biographies mention Adi Shankara traveling widely within India, Gujarat to Bengal, and participating in public philosophical debates with different orthodox schools of Hindu philosophy, During his tours, he is credited with starting several Mutts (monasteries). Ten monastic orders in different parts of India are generally attributed to Shankara's travel-inspired Sanyasa schools, each with Advaita notions, of which four have continued in his tradition: Bharati (Sringeri), Saraswathi (Kanchi), Tirtha and Asram in (Dwaraka). Other monasteries that record Shankara's visit include Giri, Puri, Vana, Aranya, Parvata and Sagara – all names traceable to Ashrama system in Hinduism and Vedic literature.

Adi Shankara had a number of disciple scholars during his travels, including Padmapada (also called Sanandana, associated with the text Atma-bodha), Sureshvara, Tothaka, Citsukha, Prthividhara, Cidvilasayati, Bodhendra, Brahmendra, Sadananda and others, who authored their own literature on Shankara and Advaita Vedanta.

WORKS

His commentaries on ten Mukhya (principal) Upanishads are also considered authentic by scholars, and these are: Bhashya on the Brihadaranyaka Upanishad, the Chandogya Upanishad, the Aitareya Upanishad, the Taittiriya Upanishad, the Kena Upanishadthe Isha Upanishad, the Katha Upanishad, the Mundaka Upanishad, the Prashna Upanishad, and the Mandukya Upanishad.  Of these, the commentary on Mandukya, is actually a commentary on Madukya-Karikas by Gaudapada.

Other authentic works of Shankara include commentaries on the Bhagavad Gita part of his Prasthana Trayi Bhasya.  His Vivarana (tertiary notes) on the commentary by Vedavyasa on Yogasutras as well as those on Apastamba Dharma-sũtras (Adhyatama-patala-bhashya) are accepted by scholars as authentic works of Adi Shankara. Among the Stotra (poetic works), the Daksinamurti Stotra, the Bhajagovinda Stotra, the Sivanandalahari, the Carpata-panjarika, the Visnu-satpadi, the Harimide, the Dasa-shloki, and the Krishna-staka are likely to be authentic.

Shankara also authored Upadesasahasri, his most important original philosophical work. Of other original Prakaranas (monographs, treatise), seventy six works are attributed to Adi Shankara. Modern era Indian scholars such as Belvalkar as well as Upadhyaya accept five and thirty nine works respectively as authentic.

Shankara's stotras considered authentic include those dedicated to Krishna (Vaishnavism) and one to Shiva (Shaivism) – often considered two different sects within Hinduism. Scholars suggest that these stotra are not sectarian, but essentially Advaitic and reach for a unified universal view of Vedanta.

Adi Shankara's commentary on the Brahma Sutras is the oldest surviving. However, in that commentary, he mentions older commentaries like those of Dravida, Bhartrprapancha and others which are either lost or yet to be found.