Patanjali was an ancient Indian guru who lived between second century BCE and fifth century CE. He was the creator of the Yoga Sutras, a four-volume classification of yogic thinking, and a prominent researcher of the Sankhya philosophy. According to scholars, Patanjali's Yoga Sutras are a cornerstone of the classical Yoga philosophy. Swami Vivekananda, born Narendranath Datta on 12 January 1863, in erstwhile Calcutta, was a Hindu spiritual leader and reformer in India who strove to reconcile Indian spirituality with western practical advancement, arguing that the two mutually reinforced and complemented each other. Influenced by western esotericism, Vivekananda played a pivotal role in introducing the Indian darsanas or teachings, of Vedanta and Yoga to the western world, and is credited with promoting interfaith harmony and elevating Hinduism to the status of a major world religion in the late nineteenth century. He eventually rose to prominence as the most illustrious disciple of the Hindu mystic, Ramakrishna, demonstrating the inherent unity of all religions. He was a pioneering figure of modern Hindu reform movements in colonial India.