Yoga (Sanskrit for “conjunction”) — is one of the six Hindu orthodox schools of philosophy (astika). It is a combination of different spiritual, mental and physical practices oriented to achieve spiritual enlightenment and liberation. The main types of yoga are: Raja yoga, Karma yoga, Hatha yoga, Jnana Yoga, Bhakti yoga, Kriya yoga. Yoga was described in the Yoga Sutras of Patanjali (ca. II century BC). Yoga principles are also elucidated in certain chapters of such Hindu sacred texts as the Vedas, the Upanishads, the Bhagavad Gita, the Hatha Yoga Pradipika, etc.