The Arya Samaj founded in 1875 by Swami Dayanand Saraswati undertook the task of reforming Hindu religion in north India.Swami Dayanand believed that there was only one God who was to be worshipped not in the form of images but as a spirit. He held the Vedas to be infallible and the fountain of all knowledge. Dayanand preached and wrote in Hindi. The Sayarth Prakash was his most important book. The Arya Samaj made rapid progress in Central India, Rajasthan, and Gujarat and particularly in Punjab where it became a very important social and political force. The members of Arya Samaj were guided by ten principles of which the first one was studying the Vedas. The rest were tenets of virtue and morality. Dayanand framed for his disciples a code of social conduct in which there was no room for caste distinctions and social inequality.
The Arya Samajis opposed child marriage and encouraged remarriage of widows. A network of schools and colleges was established throughout northern India to promote the objects of Arya Samaj.The Dayanand Anglo-Vedic School of Lahore which soon developed into a premier college of Punjab set the pattern for such institutions. Dayanand’s emphasis on the super natural and infallible character of the Vedas seems to have risen from his ardent desire to give Hinduism a definite creed and equip it with a militant character. Similar in nature was his mover for the reconversion of those Hindus who had been converted. For this purpose a purificatory ceremony called Shuddhi was prescribed.