What is yoga?
The term yoga is commonly understood as a practice that includes physical postures, breathing techniques, relaxation and meditation.
The history of yoga reveals that there is not one definitive yoga, rather yoga developed through a variety of traditions, texts and philosophical systems. The origins of yoga date back to the late Vedic period in Northern India, where ascetics followed a path of self-restraint, attempting to transcend the physical body and mind.
The first systematised approach to yoga is found in Patanjali's Yoga Sutras, arguably dated around 4th CE . Here yogic techniques are described in the Eight Limbs of Yoga: yamas (restraints), niyamas (observances), asana (posture), pranayama (control of prana by way of the breath), pratyahara (withdrawal of the mind from the senses), dharana (concentration), dhyana (meditation) and kaivalya (the final state of liberation). Only one physical posture is given in the sutras, that being a seated posture for meditation. This eight limbed path is known as raja yoga or the royal way.
In 15th CE physical postures were detailed in the Hatha Yoga Pradipika. The text describes techniques for cleansing and purifying the physical & energetic body by performing asana (physical postures), shatkarma (cleansing actions), pranayama (control of prana), mudra (seals), bandha (energetic locks), and perfection in hearing the inner sound or nadam.
Yoga was developed into an extensive physical practice notably by Krishnamacharya in the 20th century, and by his students B.K.S. Iyengar, the founder of Iyengar yoga, and Pattabhi Jois, from whom we have Ashtanga Vinyasa yoga.