The system of Asthanga Yoga was described in the book The Yoga Sutras by the Indian scholar Patañjali, who codified his thoughts and knowledge of yoga coming from ancient Sanskrit texts.
Mostly it's said that Patanjali wrote his book on Yoga somewhere between 300 B.C. and 200 A.D. In India it’s believed that Patanjali wrote also a book about grammar and aotherone about Ayurveda, but Western science says that these books have been written by another sage with the same name.
An Indian legend tells that the people were suffering and so they prayed to Vishnu to help them. They did this with the Anjali Mudra, which is formed by the hands making a bowl and raised then to the sky.
Vishnu was resting on his bed, which is formed by Adisesha (= the first Sesha, king of snakes). The king of all snakes is generally depicted with a massive form that floats coiled in space, or on the universal ocean, to form the bed for Vishnu. When Vishnu heard the praying of the people on earth and told Adisesha to reincarnate in human form and bring the people the knowledge they wanted. So Adisesha took the human form of Patanjali and fell out from heaven into the praying hands of a woman who became the mother of Patanjali. The name Patañjali comes from "Pata" to fall and "Jali" referring to the above mentioned Mudra.. Patanjali's book "The Yoga Sutras" is thus seen as a way to reduce and eliminate human suffering.
Often Patanjalis statue is white as a symbol for purity. Sometimes he holds a cone and a sword. The cone stands for knowledge (makes a sound) and the sword for the power to remove obstacles. A snake with 1000 heads forms a hood over his head. The snake stands for the ability to adapt to any climate, area and circumstances. The 1000 heads symbolise 1000 solutions for 1000 problems.
The lower part of the body is often in snake form referring to the incarnation of Adishesha, the king of snakes.