The Yoga Sutras of Patanjali are Indian sutras (aphorisms) that constitute the foundational text of yoga. The Yoga sutras incorporated the teachings of many other Indian philosophical systems prevalent at the time. Samkhya and Yoga are thought to be two of the many schools of philosophy that originated over the centuries that had common roots in the non-Vedic cultures and traditions of India.The orthodox Hindu philosophies of Samkhya, Yoga, Vedanta, as well as the non-orthodox Nastika systems of Jainism and Buddhism can all be seen as representing one stream of spiritual activity in ancient India.