Short answers, pulled from the story.
Adi Shankara was an Indian Vedic scholar-monk, philosopher, and teacher of Advaita Vedanta who lived in the eighth century CE. He is often revered in recent times as the most important Indian philosopher, though reliable information on his actual life is scant.
Scholarly-accepted dating places Adi Shankara in the first half of the eighth century CE. Earlier scholars proposed dates of 788 to 820 CE, while the Advaita tradition assigns him to the fifth century BCE.
Adi Shankara taught that the individual self, jivatman, is identical with Atman-Brahman, and that liberating knowledge of this identity brings moksha in this life. He held that the one unchanging entity, Brahman, alone is real, mediated by the Mahavakyas such as Tat Tvam Asi, "That you are."
Adi Shankara was accused of being a crypto-Buddhist because his Advaita showed influences from Mahayana Buddhism. Ramanuja called him a Prachanna Bauddha, and Bhaskara attacked Advaita as Mayavada chanted by Mahayana Buddhists. The Advaita tradition rejects the label by pointing to differing views on Atman, Anatta, and Brahman.
The legendary Shankara was created in the fourteenth century, centuries after his death, within the Vijayanagara Empire. Vidyaranya, who served as Jagadguru of the Sringeri Sarada Pitham from 1380 to 1386, created legends turning Shankara into a divine folk-hero who spread his teaching across India through digvijaya.
Works known to be written by Adi Shankara himself include the Brahmasutrabhasya, his commentaries on principal Upanishads, his commentary on the Bhagavad Gita, and the Upadesasahasri. Over 300 texts are attributed to him, but most were likely written by admirers or scholars with the same name.