One of the most famous leaders of a non-violent movement was Mohandas K. Gandhi (1869-1948), who opposed British imperial rule in India during the 20th century.
Gandhi took the religious principle of ahimsa (doing no harm) common to Buddhism, Hinduism and Jainism and turned it into a non-violent tool for mass action. He used it to fight not only colonial rule but social evils such as racial discrimination and untouchability as well.
Gandhi called it "satyagraha" which means 'truth force.' In this doctrine the aim of any non-violent conflict was to convert the opponent; to win over his mind and his heart and pursuade him to your point of view.
Gandhi was firm that satyagraha was not a weapon of the weak - "Satyagraha is a weapon of the strong; it admits of no violence under any circumstance whatever; and it always insists upon truth."
Gandhi did not think that non-violence was a tool for those who were too scared to take up arms (an accusation that was sometimes made):
My non-violence does not admit of running away from danger and leaving dear ones unprotected. Between violence and cowardly flight, I can only prefer violence to cowardice. I can no more preach non-violence to a coward than I can tempt a blind man to enjoy healthy scenes.
Gandhi, Young India, 28 May 1924
Non-violence in Gandhi's thinking was a tool that anyone could (and should) use, and it was based on strongly religious thinking:
Non-violence is a power which can be wielded equally by all - children, young men and women or grown-up people, provided they have a living faith in the God of Love and have therefore equal love for all mankind. When non-violence is accepted as the law of life, it must pervade the whole being and not be applied to isolated acts.
Gandhi, Harijan, 5 September 1936
Non-violence is an active force of the highest order. It is soul force or the power of Godhead within us.
Gandhi, Harijan, 12 November 1935
