The Holy land of India was in the throes of spiritual darkness. The dark clouds of ignorance by way of excessive and selective emphasis on rituals and priesthood threatened to engulf the true spirit of Upanishads. Under the influence of so-called 'Kali Yuga', society was plagued with casteism, cruelty, and intolerable suffering inflicted upon animals as well as underprivileged people. Dharma was on decline. Material comforts and sensual enjoyment formed the basic aim in life; spirituality took beating in the onward march of crass superstitions in the name of religion.
The cry of mass despair resulted in the advent of Buddha and Mahavir that filled the religious vacuum to some extent with their teachings of compassion and non-injury. People desisted from animal sacrifices and envisaged some respite from the tyranny of kings and their liaison with merchant and Brahmin class. Kings and the emperors adopted the new religion of equality, ahimsa, and compassion. For some time peace and prosperity prevailed in the land.
However, in their attempt to cut the dross, Buddhism and Jainism removed the basic life sustaining principles as well. Truth contained in Vedas and Upanishads was discarded; these religions refused to accept the authority of Vedas and Upanishads. Hinduism was on decline, and with it the religion as such was in danger. Soon the inevitable happened. Buddhism also showed signs of distortions and degeneration, and was on wane in this Holy land of India. What were the factors responsible for this decline? It is difficult to say, but indiscreet enrollment of many people as monks, both men and women, was one of them. Invariably the monasteries breed corruption where monks or sannyasins are admitted without proper training, and when they are incompetent to lead pure and selfless life.
Be that as it may, the lurking fire for Truth, Liberation, and Freedom can never be extinguished from the hearts of restless souls - the seekers after truth. And moreover, whether we consciously know it or not, there is always the need for true religion, for the essential human nature is ever in search of and yearns for the Final Truth. In such chaotic conditions of dominance of priesthood and karma-kanda on one hand and degenerate Buddhism on the other, the society needed a soul of great spiritual knowledge and capacity to reestablish the dharma. And as assured in the Gita, this holy land did not disappoint her children then also.
In the far off corner of southern India, presently the state of Kerala, was born (around 686 A.D., some maintain 788 A.D.) the savior of true Hinduism, who reestablished the dharma of Upanishads, the eternal religion. Shankaracharya was personification of Knowledge and Compassion combined together! No adjectives would ever be enough to sing glories about his extraordinary life, supernatural powers, and razor sharp logic, reasoning and rational analysis of epistemology. His philosophy was based on one fundamental truth, truth of personal realization of the Highest Truth.
Shankara had taken to life of sannyasin at this tender age of boyhood. This boy monk had halo around him, nimbus of purity, divinity, and godliness. No one could come in his way, for now he had turned his back on the world to seek the highest truth of Advaita. Even as a child, he walked barefoot on the path full of thorns of hardship and austerity. What a tapas! But there was no fear in the heart or eyes of the child. He had heard that the great Yogi Patanjali lived in the state of samadhi in a cave at the banks of holy river Narmada as Govindpada. He had mentally accepted him as his Guru, and thus, he reached at the tender age of eight to the banks of Narmada and became disciple of the great Govindpada.
Right from his early childhood Shankara exhibited extraordinary divine powers, rarely found in any ordinary human being. Just at the age of eight, he had learnt all the Upanishads, the Vedas, and other important Hindu Scriptures. At the age of sixteen he had written commentaries on eleven major Upanishads, Brahma Sutras, and the Bhagavad Gita. He composed most melodious verses and songs in the praise of Mother Goddess, Lord Krishna, and Lord Shiva. Unbelievable feat indeed that is possible only for supernatural soul.
Acharya Shankara preached Absolute Monism, also known as Advaita Vedanta. The basic philosophical tenet is based on only One Truth, without second - ek meva advitiya. This Reality is of the nature of Consciousness, and can be described as Sat Chit Ananda at the best! The Reality is also called as Brahman, Self, God, and Atman. The world, the nature, the Jivas and whatever we experience through our senses, as multifarious existence is illusory and therefore unreal - Maya. Thus Acharya Shankara is credited to have propounded Mayavada. Later many philosophers did not agree with his absolute monism, and they have had introduced various revisions in the philosophical basis of Advaita Vedanta of Shankara. It is very difficult to understand the nuances and subtleties therein; suffice here is to say that Ramanujacharya, Madhvacharya, Vallabhacharya, Chaitannya, and many more of recent past - Sri Ramakrishna and Swami Vivekananda - have enriched Vedanta for the benefit of humanity. For all these philosopher saints religion and philosophy were not two different things, but, in fact, religion was realization of these philosophical truths/principles in individual lives.
He established the true religion of Upanishads - Advaita Vedanta - to its highest glory. According to him transcendental realization of SELF was the sole purpose of human birth, only real knowledge, and that was the ultimate stage a person should strive to seek. For next sixteen years he wandered from place to place covering every nook and corner of this holy land, establishing Maths for spiritual renaissance and rediscovering the lost glory of Sanatana Dharma. Scores of people followed him as his monastic disciples, and householders also went along as followers of this great victorious 'king' who defeated army of scholars of Purva-Mimamsa, Samkhya, Buddhism, and Jainism one by one and freed the masses from the clutches of religious superstitions, uncertainty, and confusion.
Today Acharya Shankara is one of the most misunderstood philosophers and saints of India. People are afraid that he taught total Vairagya (renunciation) andSannyasa (life of monk) only. Many believe that for Shankara actions and karma were of no importance, however, it must be said with great emphasis that such is and was never the case. He firmly advocated karma and bhakti as the means to purification of mind, which then becomes fit for realization of Atman. His Jnana Yoga was not dry philosophy, otherwise how can one explain his reestablishing idols in hundreds of temples all over India, his mother worship, and scores of most melodious songs and hymns in the praise of Ma Annapurna, Ganga, Shiva, Krishna, Pandurang, and so on!
In fact, as no philosophical discussion can ever be complete without the mention of his name, Acharya Shankara must be credited with reviving and reestablishing Sanatana Hindu dharma amidst the danger of Truth losing to declining religions of his time, as well as to those that were to come to India later.