On this day, July 23, in 1846, naturalist writer and philosopher Henry David Thoreau left his cabin at Walden Pond for a walk into Concord, Mass., and ended up in jail for refusing to pay his $1 poll tax.

Thoreau is best known as the author of "Walden."

That night, behind the jail walls, Thoreau got the idea to write "Civil Disobedience." The essay argues that people have a duty to be just and not let governments overrule their conscience.

Thoreau, who also wrote "Walden" about his two years living off the land, coined the term Civil Disobedience to describe his refusal to pay the poll tax because of his opposition to slavery and the war with Mexico.

His arguments have been cited by Mahatma Gandhi, Martin Luther King Jr. and other activists.