Adi Shankaracharya, also known as Shankara or Shankar Bhagavatpada, was a renowned Indian philosopher and theologian who lived in the 8th century. He is considered to be one of the most influential figures in the development of Hinduism, particularly in the Advaita Vedanta school of thought. Shankaracharya's teachings and writings have left a lasting impact on Indian philosophy and spirituality.

The main beliefs of Adi Shankaracharya revolve around the concept of Advaita, which means non-dualism. According to Shankara, the ultimate reality is Brahman, the absolute, infinite, and eternal consciousness that pervades everything in the universe. He believed that Brahman is the only true reality, and everything else is an illusion or maya.

Shankaracharya emphasized the importance of self-realization or Atma Jnana, which is the realization of one's true self as Brahman. He believed that the individual self or Atman is not separate from Brahman, but is a part of it. Shankara taught that through meditation, self-inquiry, and devotion to Brahman, one can attain liberation or moksha from the cycle of birth and death.

Another important belief of Shankaracharya was the concept of maya, which he described as the power of Brahman that creates the illusion of duality and separation in the world. He believed that maya is the cause of all suffering and ignorance, and it can only be overcome through the realization of Brahman.

Shankaracharya also emphasized the importance of the Vedas, the ancient Hindu scriptures, as the ultimate source of knowledge and truth. He believed that the Vedas contain the eternal truths of Brahman and are the means to attain liberation.

In addition to his philosophical beliefs, Shankaracharya also advocated for the importance of karma yoga, the path of selfless action, as a means to purify the mind and attain spiritual growth. He believed that performing actions without attachment to the results can lead to the dissolution of the ego and the realization of the true self.

Furthermore, Shankaracharya rejected the ritualistic and idolatrous practices of his time and emphasized the importance of inner spiritual practice over external rituals. He also promoted the concept of Advaita Bhakti, the path of devotion to Brahman, as a means to attain liberation.

In conclusion, Adi Shankaracharya's main beliefs revolve around the concept of Advaita, self-realization, maya, the Vedas, karma yoga, and inner spiritual practice. His teachings have had a profound impact on Hinduism, and his legacy continues to inspire spiritual seekers to this day.