A. Henry David Thoreau.
Thoreau was an early non-violent activist and a writer who advocated peace and freedom. Henry David Thoreau advocated for peaceful, non-violent resistance in his book Civil Disobedience written in 1849 following his resistance to the Mexican-American War beginning in 1846-1848. Thoreau believed the war was about conquest and extending slavery. He resisted the growth of the government which limited the freedom of the American people.