Ayurveda: the sister science of Yoga

According to Hindu legends, Lord Shiva is credited with propounding hatha yoga. It is said that on a lonely island, assuming nobody else would hear him, he gave the knowledge of hatha yoga to his wife, Goddess Parvati - but a fish heard the entire discourse, remaining still throughout. The fish (=matsya) later became a siddha (=obtained magical powers) and came to be known as Matsyendranath. Matsyendranath taught hatha yoga to his disciple Gorakshanath and to a limbless man, Chaurangi. Hatha yoga was thus passed down in disciplic succession.

Historically, classical Hatha Yoga is described primarily in three texts of Hinduism: Hatha Yoga Pradipika by yogi Swatmarama (15th centrury BCE), Shiva Samhita by unnkown author (~16th centrury BCE) and Gheranda Samhita by yogi Gheranda (17th century BCE). Swatmarama made a complilation of earlier hatha yoga texts. He introduces his system, which is based on asanas (=physical postures) and pranayama (=breathing techniques) as a preparatory stage for physical purification of the body for the purpose of higher meditation or Yoga. Hatha Yoga Pradipika includes information about shatkarma (purification), chackras (centers of energy) and nadis (energy channels), kundalini (=instict), bandhas (=muscular locks), kriyas (cleansing techniques), Shakti (=sacred force) and mudras (=symbolic gestures) among other topics.

Many modern schools of hatha yoga in the West derive from the school of Tirumalai Krishnamacharya, who taught from 1924 until his death in 1989. Among his students prominent in popularizing yoga in the West were K. Pattabhi Jois (1915 - 2009, famous for the vigorous Ashtanga Vinyasa style), B.K.S. Iyengar (1918 - 2014, famous for emphasis on alignment and the use of props), Indra Devi (1899 - 2002, the first foreign woman among dedicated yogis) and Krishnamacharya's son T. K. V. Desikachar (born 1938, still alive and well, famous for yoga and vedic chanting). 

Another major stream of influence within and outside India has been Swami Sivananda of Rishikesh (1887–1963) and his many disciples including Swami Vishnu-devenanda (founder of International Sivananda Yoga Vedanda Centres) and Swami Satyananda of the Bihar School of Yoga (famous for Yoga Nidra).