Narendranath Datta arrived in the United States in 1893 with the intention of speaking at the World's Parliament of Religions, no delegate credentials, no organisation behind him, and not enough money. He very nearly failed to be admitted, and got in on the strength of a letter from a Harvard professor who had met him.
His opening address, delivered in September, began by addressing the audience as sisters and brothers of America, and the reception is one of the well documented moments in the history of religion in the West. He spoke on Hinduism as a tradition that had taught tolerance and universal acceptance, quoted verses about all paths leading to the same goal, and criticised sectarianism directly to an assembly convened to celebrate religious diversity.
What followed was three years of lecturing across the United States and Britain, the founding of Vedanta societies, and the publication of four books that shaped the modern presentation of Hindu practice more than any other: Karma Yoga, Bhakti Yoga, Jnana Yoga and Raja Yoga. The four yogas scheme, in which paths of action, devotion, knowledge and psychological discipline are alternative routes suited to different temperaments, is largely his organisation of the material, and it is now so widespread that it is often mistaken for an ancient classification.