However, the origins of yoga are believed to be much older than that, stemming from the oral traditions of Yogis, where knowledge of Yoga was handed down from Guru (spiritual teacher) to Sisya (spiritual student) all the way back to the originators of Yoga, "the Rishis," who first began investigation into the nature of reality and man's inner world.
According to the Yoga Sutras of Patanjali - the basic text of the Indian philosophical schools of yoga, which had a huge influence on the understanding of yoga in India and the rest of the world - the ultimate aim of Yoga is to reach "Kaivalya" (emancipation or ultimate freedom). This is the experience of one's innermost being or "soul" (the Purusa). Then one becomes free of chains of cause and effect (Karma) which tie us to continual reincarnation. In Kaivalya one is said to exist in peace and tranquillity, having attained absolute knowledge of the difference between the spiritual which is timeless, unchanging and free of sorrows, and the material which is not.
This is considered desirable as life is analyzed as ultimately full of sorrows and pain- even pleasure and joy leave pain and loss when they have gone as nothing in the material world is permanent.
There are said to be 4 main paths (Margas) by which to reach the ultimate goal of Yoga - "Kaivalya." There is the path of Knowledge (Jnana Marga) in which one learns to discriminate between what is real and what is illusory, the path of selfless work (Karma marga), the path of devotion (Bhakti Marga) and the path of control of the mind (Yoga Marga) where all the activities of the mind and consciousness are studied and brought under control. From these have come the various paths of yoga which can be followed.
Laya yoga involves absorption in god to experience ultimate bliss.
Bhakti yoga requires absolute devotion to god to achieve the ultimate goal.
Karma yoga achieves this through selfless work without thought of personal reward.
Jnana yoga is the yoga of knowledge cultivating the discrimination between spiritual reality and the illusion of the material world.
Various schools or styles of Yoga have grown around each of these paths, which emphasize different aspects of these paths, or a combination of them, in their practical methodology. Usually these schools are established by renowned teachers or gurus and reflect their methodologies and ways of practicing, teaching and following the path of yoga. Some of the most well-known modern schools or styles of yoga include: Iyengar, Astanga, Vini, Ananda, Anusara, Bikram, Integral, Kali Ray Tri, Kripalu, Kundalini and Sivananda. (See this article for a brief explanation of the differences between some of these schools at a practical level in terms of how classes are run.) Interestingly, 3 of the most popular schools today - Iyengar, Astanga and Vini Yoga - were all developed by students of Sri T. Krishnamacharya.
The varied philosophies and methodologies of Yoga itself were clearly and methodically brought together and presented by the sage Patanjali in his set called "The Yoga Sutras," written some 2200 years ago. The Sutras bring together all the various strands of theory and practice from all sources of yoga and present them in one concise, integrated and comprehensive text. How all the aspects interrelate and form part of the whole body of yoga are clearly elucidated. There are 8 disciplines to yoga as presented by Patanjali (thus Astanga yoga - 8 limbed yoga) which must be practiced and refined in order to perceive the true self- the ultimate goal of Yoga:
Yama - Universal ethics: Non-violence, truthfulness, non-stealing, sexual restraint and non-acquisitiveness.
Niyama - Principles of self conduct: purity, contentment, intense dedication or austerity, study of self and scriptures and self-surrender.
Asana - practice of the postures.
Pranayama - Breath control.
Pratyahara - withdrawal and control of the senses.
Dharana - concentration.
Dhyana - meditation.
Samadhi - a state of higher consciousness where the sense of self (ego) dissolves in the object of meditation and
the individual self exists in its own pure nature.
The key elements of all the paths of yoga are presented in a balanced perspective and legend has it that Patanjali was himself a realized being and so writing from experience.
These Sutras were and are still considered a most profound and enlightening study of the human psyche. Patanjali shows how through the practice of Yoga, we can transform ourselves, gain mastery over the mind and emotions, overcome obstacles to our spiritual evolution and attain the goal of yoga: liberation from the bondage of worldly desires. Written in Sanskrit, many commentaries and translations have been written over the centuries by various scholars and practitioners; each interpreting as per their era and understanding.