The Indus Valley was a sophisticated cosmopolitan. It was an area that hosted trade from all over because of its location on the Sarasvati or Ganges River. Some of the major cities in this civilization were Harappa and Mohenjo-Daro, these cities were discovered in the 1920's. Some people believe that Yoga can trace its roots back to this civilization due to artifacts found. One of the major artifacts is the Pasupati Seal, which is thought to depict a proto Siva.
3300-1900Rg Veda, Sama Veda, Yajur Veda, Atharva Veda The Vedas are the oldest Sanskrit Texts. They are hymns revealed to the rishis, the seers of the Vedas. The Vedas described rituals for gaining a better quality of life and afterlife. Some of the Deities honored in the Vedas are Indra, Rudra, and Agni. Yoga here is used to mean yoking "as in yoking an ox to a cart" The time was like the wild west, with lots of horses and cattle, roundups plus big fire ceremonies
1500-1000 BCEBrhadaranyaka and Chandogya Upanisads
700-500 BCESamkhya is a way of understanding the metaphysical constuction of the world. Though it is not often admitted, Samkhya is the underline cosmology used by many Indic Traditions. The Upanisads, The Bhagavad Gita, Patanjali's Yoga Sutra are all based on the samkhya cosmology.
2nd-3rd CenturyFirst Definition of Yoga given by Yama, the God of Death, to Naciketas as the metaphore of the charioteer. "The body is the chariot itself, the self or soul is the a rider in the chariot, the intellect is the charioteer, the mind is the reins, the senses the horses, and the sense objects are the paths taken by the senses." (3.3-4)
3rd Century BCE