Yoga originated in India. It is impossible to say anything authoritatively with regard to its time of origin, but it certainly is of a great age. It can be called ageless since it is believed to have been taught initially by the Lord. Both Lord Krishna (divine incarnation of Lord Vishnu) and Lord Shiva are known as the originators of yoga.
In the Bhagvad Gita (chapter IV), Lord Krishna tells Arjuna that he preached this timeless knowledge of yoga first to Vivasvat (sun) many years ago. Vivasvat then preached it to his son Vaivasvat Manu (the first man of the human race). Manu gave that knowledge to his son, King Ikshavaku, and from Ikshavaku the knowledge of yoga was passed on to many rajarshis (royal sages) in traditional succession.
But after a long lapse of time, the true knowledge of yoga disappeared and none could master it. So, once again Lord Krishna revealed the true knowledge of that very same ancient yoga to his beloved friend and devotee Arjuna on the battlefield of the great Mahabharata war. Manu is regarded as the progenitor of the human race for the period of nearly 306.72 million years. Vaivasvat Manu, referred to above, is considered to be the progenitor of the present race of human beings. Out of 306.72 million years (that is the life span of the present Manu); 120.53 million years have already passed. We are at present living in the twenty-eighth kali yuga, which is supposed to have begun February 13, 3102 B.C. That means Vaivasvat Manu received the knowledge of yoga from his father Vivasvat nearly 120.53 million years ago, but Vivasvat received it from the Lord even earlier than that. This indicates the timelessness of yoga.
In the third century BC the great sage Patanjali reviewed all of the practices of yoga that had been validated by the ancient yogis of India. He identified the theme of yoga, clarified its methods, and organized its techniques into a progressive system of exercises. After a long journey through innumerable currents of Indian metaphysical thought and mystical experience, Yoga was finally lifted out of its hazy past and presented as a scientific classical discipline.
The ‘Yoga Sutras of Patanjali’ is a masterpiece. It has stood the test of time and experience. It has served as the most authoritative and practical handbook available to those who have taken to the deeper and more systematic practices of yoga.
Patanjali established yoga as a precise discipline with eight essential practices:
(1) Yam, the five rules of moral restraint;
(2) Niyam, the five rules of moral observance;
(3) Asan, the practice of Yoga postures;
(4) Pranayam, the practice of breath control;
(5) Pratyahar, the withdrawal of mind from the senses;
(6) Dharana, the practice of mental focusing;
(7) Dhyan, the practice of meditation; and
(8) Samadhi, the state of super consciousness and perfect equanimity.
This system is known as Asthang Yoga, or the eight fold path of yoga is the realization of the spirit within. The eight disciplines of Asthang yoga are progressively designed to purify the body and mind. This allows the yogi to focus on the inner spirit.
Astang Yoga is comprised of three distinct groups of spiritual exercises. The first two limbs are known as yam and niyam. Together they provide a moral code of conduct for the yoga aspirant. These restraints (yams) and vows (niyams) cultivate the ethical behavior essential to the pursuit of the spiritual goal.
The second group is composed of bahirangs, or external practices, which include asan, pranayam, and pratyahar .This group is called Hatha Yoga .These practices focus primarily on physical discipline. They strengthen the body, increase the vital force, and quite the mind.
The third group is known as Raja Yoga, which includes the antarangs (internal practices) of dharana, dhyan and Samadhi. The practice of Raja Yoga focuses on the mental concentration required for Samadhi, the state of super consciousness.