The origins of Yoga may date back to pre-vedic Indian traditions. The earliest accounts of yoga-practices are to be found in the Buddhist Nikayas. Parallel developments were recorded around 400 CE in the Yoga Sutras of Patanjali, which combines pre–philosophical speculations and diverse ascetic practices of the first millennium BCE with Samkhya-philosophy. Hatha yoga emerged from tantra by the turn of the first millennium.
Gurus from India later introduced yoga to the west, following the success of Swami Vivekananda in the late 19th and early 20th century. In the 1980s, yoga became popular as a system of physical exercise across the Western world. This form of yoga is often called Hatha yoga.
Yoga physiology described humans as existing of three bodies and five sheets which cover the atmman, and energy flowing through energy channels and concentrated in chakras.