Yoga goes back to the age of the Vedas or even before. Researchers have traced it back to about 5000 years old. The earliest Rig Veda mentions about yoga, and there are pictographic proofs found in the seals of the Indus Valley Civilization. Bhagavad Gita and the Shanti Parva of the Mahabharata elaborately talk about it. Later, Patanjali had compiled the ‘Yoga Sutras’ which became the go-to book for yoga and made him the ‘Father of Yoga’. The history can be divided into four stages.
Preclassical (Upanishad) period (800 BC to 250 BC)
The Upanishads, Mahabharata and the Bhagavad Gita contain several references to yoga. The Bhagavad Gita mentions may forms of yoga: Jnana yoga, Bhakti yoga, Karma yoga and Raja yoga. Krishna, during the Gitopadesha, explains that if a person seeks reality with humility and reverence, they can attain a higher state of consciousness. In this period, yoga was more of lifestyle rather than breathing or a posture-related practice
A couple of centuries later the mind and body was used as a means to attain enlightenment giving rise to Tantra Yoga and Hatha Yoga
Classical Period (184 BC to 148 BC)
During the classical period, Patanjali compiled 195 sutras (aphorisms) of yoga into a more concise form. It has the classical eight limbs: Yama (social conduct), Niyama (personal conduct), Asana (physical postures), Pranayama (breathing regulation), Prathyahara (withdrawal of senses), Dharana (concentration), Dhyana (meditation) and Samadhi (transcendence). Patanjali’s yoga came to be known as Ashtanga Yoga.Though, Patanjali added physical postures and breathing regulation to yoga, they were used only as practices secondary to Dhyana and Samadhi.
Post classical period (800 AD to 1700 AD)
During this age, followers of Patanjali yoga gave yoga a new outlook by giving greater importance to the asanas, kriyas and pranayama, for cleansing of the body and mind. The purification of body and mind helped practitioners reach higher levels of practice, like Samadhi.
The new age of Yoga began with teachers travelling far and wide teaching Yoga starting from the late 1880s to forming stable institutions in the 1930s the practice of Hatha Yoga continues till date in newer formats with newer ones coming up from time to time.
Modern period (From 1863 AD onwards)
Swami Vivekananda mentioned Yoga in his historic speech at the Parliament of Religions in Chicago. Many yogis like Maharishi Mahesh Yogi, Paramahamsa Yogananda, Ramana Maharishi , influenced the western world profoundly through their spiritual accomplishments. Gradually yoga was accepted throughout the world as a secular spiritual practice rather than a ritual-based religious doctrine.
In recent times, T.Krishnamacharya trained three disciples, BKS Iyengar, Pattabhi Jois and TVK Desikachar. These yoga masters popularized yoga globally.