The beginning of the yoga tradition originated in India can be traced back from the period of Indus Valley Civilization (300-200 BC).  The seals of meditative postures excavated from Harappa and Mohanjodaro bear ample evidence that the history of transcendental thought and spiritual practice in India had begun at a far earlier period than that of the Indus Valley Civilization.

Another outstanding figure in the line of yoga tradition is that of Gautama Buddha (563-483 BC).
 
The Indian philosophy in the pre-Buddhist Sanskrit works such as the Upanishads and the Bhagavad Gita has moulded yoga system of thought. It has undergone a metamorphosis over many millennia. The Gita itself refers to yoga as an ancient system.

Patanjali’s Yoga Sutra (Between AD 400-500) is a concise and compact text on yoga. It is very much scientific and systematized.