1442: The Portuguese bring 10 captives from Africa to Europe, beginning the transatlantic slave trade.
1619: The first African slaves arrive in the North American colonies.
1775: The first organization to aid fugitive slaves is formed in Philadelphia, Pennsylvania.
1777: Vermont is the first state to ban slavery.
1780: Pennsylvania becomes the first state to pass a gradual emancipation law.
1787: Slavery is protected within the United States Constitution.
1793: Congress passes the first federal Fugitive Slave Law, making it illegal to aid slaves fleeing from slavery.
1808: The international slave trade is outlawed, but this causes the American domestic slave trade to grow.
1816: The American Colonization Society is founded with the goal of resettling former slaves in either Africa or Latin America.
1822: John Rankin moves from Kentucky to Ripley, Ohio, and enlarges Underground Railroad operations already in existence there.
1826: Levi Coffin moves to Fountain City, Indiana, and establishes a station on the Underground Railroad that will become one of the most important in the nation.
1831: Nat Turner leads a slave revolt in Virginia during which 60 white people are massacred, leading to harsh reprisals against all black people.
1831: Editor William Lloyd Garrison calls for immediate emancipation in the first issue of The Liberator.
1833: England outlaws slavery in its colonies, including Canada.
1833: The American Anti-Slavery Society is formed in Philadelphia.
1835: The New York Committee of Vigilance is formed in Manhattan and becomes a model used by other Underground Railroad organizers.
1838: “Eliza,” the woman who is the model for a character in Uncle Tom’s Cabin, escapes to freedom through the Underground Railroad in Ripley, Ohio.
1838: Frederick Bailey escapes from slavery in Maryland and changes his name to Frederick Douglass.
1845: Captain Jonathan Walker is arrested for aiding fugitive slaves in Florida and his hand is branded.
1849: Harriet Tubman escapes from slavery in Maryland.
1849: The Reverend William King founds a settlement for blacks in Buxton, Ontario.
1851: The Christiana Riot in Lancaster County, Pennsylvania, prevents slave catchers from capturing fugitives and results in the death of slaveholder Edward Gorsuch.
1854: The Kansas-Nebraska Act is passed, allowing western territories to vote on whether they want to be free states or slave states. This leads to a mini civil war in Kansas.
1859: John Brown tries to launch a slave revolt at Harper’s Ferry, Virginia, but is captured, tried, and executed.
1861: Eleven slave states secede from the United States, forming their own country called the Confederate States of America. This leads to the Civil War between the Confederacy of the South and the Union of the North, which lasts until 1865.
1865: The Civil War ends and the 13th Amendment to the Constitution is ratified, which abolishes slavery in the United States forever.