The Vedas were a collection of science of Mother Nature, agriculture, mathematics, astronomy, social sciences, ethics & morality, culture, arts, Ayurveda, and much more. Vedas are composed in to sacred songs, mantras and rituals which were taught during that time. Vedas have four parts, Aranyaka, Samhita, Brahman and Upanishads. In Upanishads, the first explicit references to yoga appear. Concepts of withdrawing the senses, controlling the mind, and attaining liberation are the main objectives in Upanishads.