In the decades before the Civil War, anti-slavery sentiment sparked an abolitionist movement that employed risky and radical tactics to bring an end to slavery. Abolitionist ideas became increasingly prominent in Northern churches and politics beginning in the 1830s, which contributed to the animosity between North and South leading up to the Civil War. In early 1831, Garrison, in Boston, began publishing his famous newspaper, the Liberator, supported largely by free African-Americans. In December 1833, the Tappans, Garrison, and sixty other delegates of both races and genders met in Philadelphia to found the American Anti-Slavery Society. All these activities provoked widespread hostile responses from North and South, most notably violent mobs, the burning of mailbags containing abolitionist literature, and the passage in the U.S. House of Representatives of a “gag rule” that banned consideration of antislavery petitions. By the later 1850s, organized abolitionism in politics had been subsumed by the larger sectional crisis over slavery prompted by the Kansas-Nebraska Act, the Dred Scott decision, and John Brown’s raid on Harpers Ferry. Most abolitionists reluctantly supported the Republican Party, stood by the Union in the secession crisis, and became militant champions of military emancipation during the Civil War.