The word yoga means 'union' in Sanskrit, the language of ancient India where yoga originated. We can think of the union occurring between the mind, body and spirit. In India, Yoga is considered one of the six branches of classical philosophy and is referred to throughout the Vedas - ancient Indian scriptures and amongst the oldest texts in existence.The Upanishads are also broadly philosophical treatises which postdate the Vedas and deal with the nature of the 'soul' and universe.