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The British Atlantic Slave Trade flourished during the 18th century with the rise of sugar, tobacco, and rice. These cash crops increased demand for enslaved African labor in the Americas. Slavery has been part of the history of the United States since the 17th century. During the colonial era, many laws preserved and reinforced the institution of chattel slavery, where enslaved people were treated as private property. This timeline explores legal and social events that impacted individuals, enslaved and free, from the founding of the nation to the Civil War. 

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1770, March 5

Boston Massacre

Violence erupted in Boston between an unruly crowd of American colonists and British soldiers after tension over acts the British Parliament implemented in the colonies. On March 5, Crispus Attucks, believed to be formerly enslaved, became a martyr for the patriots' cause. Ten other colonists were injured or killed during the Boston Massacre. The incident was depicted by Paul Revere the patriotic silversmith, in his famous copperplate engraving. 

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Poems on Various Subjects, Religious and Moral

Phillis Wheatley's Poems on Various Subjects, Religious and Moral was the first book published by an African American woman. Born in Africa and captured by slave traders, Wheatley ended up in Boston, Massachusetts, where she learned to read and write.

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1775, November 7

Lord Dunmore's Proclamation

In 1775, John Murray, fourth Earl of Dunmore and the last Royal Governor of Virginia declared, "all indented servants, Negroes, or others, (appertaining to Rebels,) free, that are able and willing to bear arms, they joining His Majesty’s Troops…" This decree allowed free and escaped Africans to join the British in the American Revolution.

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Continental Army

George Washington initially opposed allowing free or enslaved Africans to fight in the Revolutionary War. He changed his mind when the British began offering freedom to those enslaved who fought against their patriot owners. Ultimately, Washington saw an estimated 5,000 black soldiers—free and enslaved—fight for the colonies. 

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1776, July 4

Declaration of Independence

In June 1776, Thomas Jefferson wrote a rough draft of the Declaration of Independence which included a section about slavery. The final draft, which included dozens of changes, no longer included the following text "...he [King George] has waged cruel war against human nature itself, violating it's most sacred rights of life & liberty in the persons of a distant people who never offended him, captivating & carrying them into slavery in another hemisphere…"

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Vermont Abolishes Slavery

Vermont's legislators banned slavery in July 1777, however, there were still many laws and restrictions placed on free blacks within the colony.

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Gradual Emancipation Laws

Over the next few decades, many states enacted gradual emancipation laws: Pennsylvania 1780, Massachusetts and New Hampshire 1783, Connecticut and Rhode Island 1784, New York 1799, and New Jersey 1804. The laws varied by state and often restricted the lives of those they freed.

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Brom and Bett v. Ashley

Brom and Elizabeth Mum Bett were enslaved in Massachusetts and sued for their freedom under the Massachusetts Constitution of 1780. They won, becoming the first enslaved people to win their freedom under the constitution.

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The state of Virginia passed legislation permitting slaveowners to free enslaved people without a special act from the governor and General Assembly. To ensure owners were not using manumission as a way to save themselves the expense of caring for enslaved people, the state required those freed who could not provide for themselves “shall respectively be supported and maintained by the person so liberating them, or by his or her estate”.

From this moment forward, if George Washington had the financial ability he legally could have freed the enslaved people he owned. 

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The New York Manumission Society

John Jay founded The New York Society for the Manumission of Slaves. In 1785, he expressed his views, writing, “I wish to see all unjust and all unnecessary discriminations everywhere abolished, and that the time may soon come when all our inhabitants of every colour and denomination shall be free and equal partakers of our political liberty.” 

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Washington's Changing Views

Throughout the 1780s and 1790s, Washington stated privately that he no longer wanted to be a slaveowner, that he did not want to buy and sell slaves or separate enslaved families, and that he supported a plan for gradual abolition in the United States. Yet, Washington did not always act on his antislavery principles. He avoided the issue publicly, believing that bitter debates over slavery could tear apart the fragile nation.

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I never mean (unless some particular circumstance should compel me to it) to possess another slave by purchase: it being among my first wishes to see some plan adopted by the legislature by which slavery in the Country may be abolished by slow, sure, & imperceptible degrees.”

George Washington, 1786

Northwest Ordinance

The Confederation Congress approved the Northwest Ordinance in 1787 and two years later, the first United States Congress renewed it. It stated “There shall be neither slavery nor involuntary servitude in the said territory, otherwise than in the punishment of crimes whereof the party shall have been duly convicted: Provided, always, That any person escaping into the same, from whom labor or service is lawfully claimed in any one of the original States, such fugitive may be lawfully reclaimed and conveyed to the person claiming his or her labor or service as aforesaid.”

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Anti-Slavery Medallions

British potter Josiah Wedgwood first produced this medallion in 1787. Conceived as an abolitionist society’s symbol, these medallions found universal appeal as a humanitarian symbol calling for the end of the African Slave Trade. Wedgwood sent several to Benjamin Franklin who distributed them. Franklin wrote of the medallions, “I am persuaded it may have an Effect equal to that of the best written Pamphlet.”

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1788, June 21

US Constitution Ratified

In 1787, George Washington presided over 55 delegates from 12 states (Rhode Island did not attend) at the Constitutional Convention. One of the key delegates, today known as the "father of the Constitution," was James Madison. While the word slave or slavery could not be found within the Constitution, there were three compromises that directly dealt with the institution of slavery: enumeration, slave trade, and fugitive slaves.

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Article I, Section 2, the Three-Fifths Compromise, counted one enslaved person equal to three-fifths of a free person in determining a state's population. This was significant in establishing taxes, seats within the House of Representatives, and the Electoral College, which elects the president. "Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons.

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Article I, Section 9, the Slave Trade Clause, prevented Congress from ending the United States' involvement in the Atlantic Slave Trade for 20 years. "The Migration or Importation of such Persons as any of the States now existing shall think proper to admit, shall not be prohibited by the Congress prior to the Year one thousand eight hundred and eight, but a Tax or duty may be imposed on such Importation, not exceeding ten dollars for each Person."

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Article IV, Section 2, the Fugitive Slave Clause, required those "held to Service or Labour", meaning apprentices, indentured servants, and enslaved people, had to be returned to their state if they were found to have run away. "No Person held to Service or Labour in one State, under the Laws thereof, escaping into another, shall, in Consequence of any Law or Regulation therein, be discharged from such Service or Labour, but shall be delivered up on Claim of the Party to whom such Service or Labour may be due."

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1789, April 30

George Washington Inaugurated


Naturalization Act of 1790

For immigrants seeking American citizenship, this law created a uniform rule for naturalization and stated that "any alien, being a free white person" who had lived in the United States for two years could petition for naturalization.

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Capital Moved to Philadelphia

Washington used enslaved labor during his presidency. When the national capital moved from New York City to Philadelphia in 1790, Washington realized that the eight enslaved workers in his presidential household might take advantage of Pennsylvania’s emancipation law. The laws allowed enslaved visitors to claim their freedom after six months of residence in the state. To evade the statute, the Washingtons sent their enslaved cook, waiters, and maids out of state every six months.

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Haitian Revolution

In August 1791, an uprising of enslaved people began in the French colony of Saint-Domingue in the West Indies. It ultimately ended with the colony's independence in 1804.

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1791, December 15

Bill of Rights Ratified


Militia Act of 1792

The Militia Act required that "every free able-bodied white male citizen" join the militia but prevented free African American citizens from joining until it was amended in 1862.

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Fugitive Slave Act of 1793, 1850

Although the Constitution included the Fugitive Slave Clause, which required the return of an enslaved person who had run away, slaveholders were frustrated by a lack of enforcement. Those who ran away often found safe havens in free states and territories. This changed under the Fugitive Slave Act of 1793, which required all states regardless of their laws to return escaped enslaved people. 

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Cotton Gin

Towards the end of the 18th century and especially in the first few decades of the 19th century there was a shift in agriculture in the southern states. Eli Whitney received a patent for the cotton gin in 1794 and it played a major role in this shift. Once the time-consuming process of cleaning cotton was no longer the slowest step, cotton production drastically increased and every decade after 1800 raw cotton yield doubled. 

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Washington's Will

In his 29-page will, Washington directed that the 123 enslaved people he owned directly be freed at his wife’s death. He emancipated his former valet, William Lee, immediately and provided him a $30 annual pension. Washington was the only founding father to enact a large-scale manumission in his will.

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Gabriel's Rebellion

For weeks, Gabriel planned a revolt with other enslaved people in and around Richmond, Virginia. On the night they planned to act, a storm broke out, causing the revolt to be postponed. By this time, law enforcement was aware and began arresting those involved. For about a month they could not locate Gabriel. Eventually, he was found, tried, and sentenced to hang along with 25 others. While the revolt never occurred, the group's ability to organize and stockpile weapons shocked much of the white community.

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Louisiana Purchase

The federal government purchased 828,000 square miles of land from France for 11 million dollars. During the coming years, there would be much debate and bloodshed over whether or not slavery would expand into this territory.

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Britain Ends International Slave Trade


Earliest Possible End Under the Constitution

1808 was the first year under Article I, Section 9 of the US Constitution that Congress could end the United States' involvement in the Atlantic Slave Trade. On January 1, 1808, An Act to Prohibit the Importation of Slaves into any Port or Place Within the Jurisdiction of the United States went into effect. 

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War of 1812

Individuals of African descent served on both sides of the War of 1812. Similar to the Revolution a proclamation was issued by the British navy that would allow residents of the United States to enter into service of His Majesty. Or individuals and families could present themselves and be sent as free settlers to a British colony. While the proclamation did not specifically mention enslaved people, it was clear that those enslaved could receive their freedom. 

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Missouri Compromise

The Missouri Compromise created the precedent for admitting new states in pairs to maintain the balance of power in Congress between free and slave states. Missouri was admitted as a slave state at the same time Maine became a free state. The act was amended to prohibit slavery north of the 36º 30' latitude line in the Louisiana Territory.

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Mexico Abolishes Slavery


Underground Railroad

The Underground Railroad was a network of individuals who helped enslaved people escape to freedom.

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Nat Turner's Rebellion

In the early hours of August 31, 1831, Nat Turner led a group of enslaved people who ultimately killed more than 55 white people. Turner and 18 others were captured and sentenced to death. In response to the rebellion, Virginia tightened laws on the state's enslaved community.

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Slavery Abolition Act

British Parliament passed this act which, beginning in 1834, abolished slavery throughout the British Empire. As part of the act, slaveholders were compensated for their loss of property.

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Texas Independence

For decades, American slaveowners moved west in large numbers into Texas, a Mexican territory. After Mexico abolished slavery, in 1829, tensions rose until finally, slaveowners declared a revolution. After about six and a half months of fighting the Mexican government, the slaveowners declared victory. In 1845, the territory was annexed as a slave state into the United States, this triggered the Mexican-American War. 

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SEC. 9. All persons of color who were slaves for life previous to their emigration to Texas, and who are now held in bondage, shall remain in the like state of servitude...”

Constitution of the Republic of Texas, 1836

Gag Rule

The gag rule halted Congressional debates on slavery. It took aim at the thousands of petitions abolitionists sent to Congress every year. John Quincy Adams believed that this rule violated people’s Constitutional right to petition the government. He became a staunch opponent of the gag rule until it was receded in 1844.

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Amistad Mutiny

In 1839, a group of enslaved Africans aboard the Spanish ship Armistad sailed from Cuba. While onboard, they rebelled and killed the captain and enslaved cook. The ship docked near Long Island, New York, where the Africans were arrested for murder and piracy on the high seas. John Quincy Adams argued for them before the Supreme Court and won. 

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Prigg v. Pennsylvania

Edward Prigg forcibly captured and returned Margaret Morgan to Maryland in violation of Pennsylvania’s state laws. Morgan’s case was brought before the US Supreme Court and the judges upheld the Fugitive Slave Clause of the Constitution. The controversial decision viewed slaveholders as having a Constitutional right to reclaim enslaved people who had run away in all states and territories of the United States. 

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Narrative of the Life of Frederick Douglass, an American Slave

Born into slavery, Frederick Douglass escaped and became an outspoken abolitionist. Audiences were so impressed with his oratory skills they questioned if he had actually been enslaved. Douglass decided to write an autobiography. Published in 1845, Narrative of the Life of Frederick Douglass, an American Slave, became so popular he had to flee to England to avoid being captured and reenslaved. While there, crowds helped raise funds so he could buy his freedom. After doing so, Douglass returned to the United States, founded an abolitionist newspaper, The North Star, and continued fighting for an end to slavery.

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Mexican-American War

The Treaty of Guadalupe Hidalgo ended the Mexican-American War and changed the southern boundary of the United States to the Rio Grande River. This land included what became California, Utah, Nevada, Arizona, and New Mexico. Americans struggled over if slavery would be permitted in this territory.

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Free Soil Party

Founded in 1848, the Free Soil Party's main platform was preventing the spread of slavery into new territories. Their slogan was "free soil, free speech, free labor, and free men."

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Harriet Tubman Escaped

Harriet Tubman successfully escaped slavery in 1849. She then returned to slave states several times to free dozens of family members and friends.

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“Ain't I a Woman?"

Born into slavery, Sojourner Truth became an outspoken advocate for abolition along with other issues. At the Women's Rights Convention in 1851, Truth gave a very powerful speech entitled "Ain't I a Woman?" highlighting racial and gender challenges faced by African American women.

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Uncle Tom's Cabin

Harriet Beecher Stowe's Uncle Tom's Cabin explored the evils of slavery. Originally published in 1851 as a series of more than 40 installments in the abolitionist newspaper The National Era, the following year it was compiled into a two-volume book. The Bible was the only book to outsell it in the 19th century.

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Twelve Years A Slave

Solomon Northup published Twelve Years a Slave: Narrative of Solomon Northup, a Citizen of New-York, Kidnapped in Washington City in 1841, and Rescued in 1853, From a Cotton Plantation Near the Red River, in Louisiana. In the first three years, more than 30,000 copies were sold.

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Kansas-Nebraska Act

The Kansas-Nebraska Act repealed the Missouri Compromise and allowed territory residents to determine whether slavery would be legal within their borders. Immediately proslavery settlers crossed into Kansas from the slave state of Missouri, clashing violently with abolitionist settlers. Newspapers across the country reported on the horror occurring in "Bleeding Kansas".

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Republican Party Founded

The Republican Party formed in response to the Kansas-Nebraska Act and opposed slavery. It also led to the end of the Whig Party. 

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Dred Scott v. Sandford

Born into slavery, Dred Scott and his wife Harriet lived in Illinois and the Wisconsin Territory, where slavery was illegal under the Missouri Compromise. After the Scotts moved to Missouri, they turned to the courts for protection, arguing that having lived in Illinois and Wisconsin Territory they were free. The Supreme Court ruled that enslaved people were not citizens and therefore did not receive protection from the courts or federal government. Furthermore, Congress did not have the authority to prohibit slavery in territories.

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John Brown’s Raid

In 1859, Harpers Ferry, Virginia was the site of John Brown's Raid on the federal armory. A staunch abolitionist, Brown viewed slavery as an immoral and corrupt institution, which could only be abolished through armed violence. His failed slave rebellion ignited longstanding tensions between the North and South.

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Presidential Election

The issue of slavery splintered the Democratic Party into northern and southern fractions during the presidential election of 1860, with each faction endorsing its own candidates. This situation allowed Abraham Lincoln, the sole Republican candidate, to win the presidency without a single Electoral College vote from a southern state.

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1860, December 20

South Carolina Seceded

On December 20, 1860, South Carolina seceded from the United States. By the end of January 1861, Mississippi, Florida, Alabama, Georgia, and Louisiana had also seceded.

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American Civil War

From April 12-14, 1861, Fort Sumter in Charleston, South Carolina was attacked by the Confederate States of America. It was the first armed conflict in the American Civil War, fought over the institution of slavery.

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January 1, 1863

Emancipation Proclamation

This proclamation issued by President Abraham Lincoln stated: “all persons held as slaves within any State or designated part of a State, the people whereof shall then be in rebellion against the United States, shall be then, thenceforward, and forever free". While it freed millions but not all enslaved people. It only freed those who were in states that had rebelled against the United States and were not yet under the control of the Union Army. It also left those people in slave states that had not seceded (Delaware, Kentucky, Maryland, Missouri, and West Virginia) enslaved. 

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The Civil War did not end slavery in the United States. Ratified on December 6, 1865, the 13th Amendment to the Constitution officially abolished slavery, it took another one hundred years for the Civil Rights Acts to be enacted, and entrenched racism is still visible today.

Suggested Readings

Baptist, Edward. The Half Has Never Been Told: Slavery and the Making of American Capitalism. New York: Basic Books, 2014.

Beckert, Seven. Empire of Cotton: A Global History. Penguin Random House, 2015.

Berlin, Ira and Ronald Hoffman, editors. Slavery and Freedom in the Age of the American Revolution. Charlottesville: The University of Virginia Press, 1983.

Hammond, John and Matthew Mason. Contesting Slavery: The Politics of Bondage and Freedom in the New American Nation. Charlottesville: The University of Virginia Press, 2011.

Horn, James, Jan Lewis, and Peter Onuf, editors. The Revolution of 1800: Democracy, Race, and the New Republic. Charlottesville: The University of Virginia Press, 2002.

Library of Congress. “A chronology of key events in the history of African American military service.”

Mason, Matthew. Slavery and Politics in the Early American Republic. Chapel Hill: The University of North Carolina Press, 2006.

Monticello. “Thomas Jefferson: Liberty & Slavery.”

Montpelier. “The Mere Distinction of Colour.”

Montpelier. “Slavery, the Constitution, and a Lasting Legacy.”

National Geographic. “A History of Slavery in the United States.”

National Park Service. “African Americans In The Revolutionary Period.”

The New York History Blog. “Black Americans in the Revolutionary War.”

Oakes, James. Freedom National: The Destruction of Slavery in the United States, 1861-1865. New York: W. W. Norton & Company, 2012.

Office of the Historian, U.S. House of Representatives. “The Interim Federal Capital in Philadelphia.”

Palliser, Jerome. “The Hidden Life of Crispus Attucks.” Journal of the American Revolution. March 5, 2014.

Rosenthal, Caitlin. Accounting for Slavery: Masters and Management. Cambridge: Harvard University Press, 2018.

Thompson, Mary. “The Only Unavoidable Subject of Regret” George Washington, Slavery, and the Enslaved Community at Mount Vernon. Charlottesville: The University of Virginia Press, 2019.


Slavery in the United States Timeline researched and written by Jeanette Patrick, George Washington's Mount Vernon 
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