Adi Shankaracharya (788 CE - 820 CE), left an indelible mark on Hindu religion and Vedic Dharma. He was the first to consolidate Advaita Vedanta. It is one among the three sub-schools of Vedanta philosophy.
Adi Shankaracharya was born to a Brahmin couple in a very small village known as Kaladi in Kerala. Even today you can visit Kaladi and visit the two shrines dedicated to Dakshinamurthy and the other to Goddess Sharada (Saraswati). You can also visit his place of birth.
The young boy adopted Sanyasa and left Kerala to find his guru. Govinda Bhagavatpada accepted Shankara as his disciple after testing his knowledge in Vedas. The guru wanted that Shankara should write commentry on the Brahma Sutras. Shankara continued his journey to Banaras. There he composed five slokas named as Manisha Panchakam. In the mean time he got many disciples.
Adi Shankaracharyas proceeded to write his well renowned Bashyas (His Commentaries) and Prakarana granthas ("treatises of philosophy").at Badari.. At Srisailam he wrote Shivanada Lahari, a sloka praising Lord Shiva. Later he also composed Lakshmi-Narasimha Stotra. This was to thank Lord Narasimha. The Lord has saved Adi Shankaracharya was from a kapalika (savage).
The monk further travelled to Gokarna temple, then to Mookambika temple at Kollur and finally to Sringeri. At Sringeri he instituted Sharadha Peetam (seat of Sharada).. Soon after this the monk commenced his Dig-Vijaya (Tour to Conquest) and travelled all over India and during his journey was propagating the philosophy of Advaita. On his way he entered and engaged debate with Buddhist and Jain monks and other Hindu scholars e.g. Neelakanta..
Later Adi Shankaracharya travelled to Sharada Peetam located in (now Pakistan Occupied) Kashmir. There are also he conquered people belonging to different scholastic disciplines i.e. Vedanta, Mimamsa.
After spending thirty two years of fruitful life, Adi Shankaracharya established the Vedic Dharma. What you enjoy today as your Hindu religion is due to the efforts of this monk. For this he debated and conquered more numerous, significant and powerful scholars and monks. He was able to overpower them single handedly to establish the Shanmatha (six-important faiths or Hindu religious sects) i.e. Saivam (Lord Shiva), Vaishnavam (Lord Vishnu), Saktham (Goddesses), Souram (Lord Surya or Sun God), Ganapathyam (Lord Ganapathy) and Skandam (Lord Subramanya).