In the 1840s, Alcott and Thoreau refused to pay the poll tax in Concord in protest against slavery. Thoreau was jailed briefly in July of 1846 for this refusal. In 1848, he delivered a lyceum lecture on the subject of civil disobedience. In 1849, his "Resistance to Civil Government" — later known as Civil Disobedience — first appeared in the one and only issue of Elizabeth Peabody's Aesthetic Papers. He urged obedience to higher laws than the temporal laws of civil government. He wrote, "This people must cease to hold slaves, and to make war on Mexico, though it cost them their existence as a people."
Several attempts to enforce the hated Fugitive Slave Law of 1850 were highly publicized and drew the attention of the Transcendentalists. In February of 1851, Shadrach Minkins, a runaway slave rescued from the courthouse in Boston, spent a night in Concord en route to safety in Canada via the Underground Railroad. In 1851, the case of Thomas Sims prompted Emerson to take a more radical stand regarding the necessity of opposing the institutionalization of slavery through the Fugitive Slave Law. On July 4, 1854, Thoreau delivered his powerful address "Slavery in Massachusetts" in response to the case of Anthony Burns. Bronson Alcott participated in an unsuccessful attempt to free Burns.
Emerson and Thoreau were among the many in Concord and Boston who saw in John Brown a man of principle, action, and disregard for personal safety rather than a fanatic. They both helped to create the image of Brown as saint and martyr. Thoreau lectured on Brown ("A Plea for Captain John Brown") as Brown's execution approached late in 1859.
