The caste system, a peculiarity of Hinduism is thought to have emerged after the deities sent the 'Deluge', which is a relentless flood in many cultures. 'Manu', a progenitor of mankind, was informed about it by 'Matsya' the 'avatar' of Lord Vishnu. 'Manu' then wrote a treatise of why the flood occurred. He believed that, as the civilizations had become depraved, they needed to be segregated into castes. Thus, the much debated caste system amongst the Hindus came into existence.