American Abolitionists and Antislavery Activists:
Conscience of the Nation

Updated April 4, 2021

l to r: Frederick Douglass, William Lloyd Garrison, Wendell Phillips

International Abolition and Anti-Slavery Timeline

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International Abolition and Anti-Slavery Timeline



The Pennsylvania Colony prohibits enslavement for more than 10 years or after the age of 24.  The Rhode Island Colonial Assembly declares slavery illegal.  This legislation is reversed in 1700 and slavery survives in Rhode Island for more than 150 years.



In England, Chief Justice Holt rules against the legal basis for slavery.  He writes, “As soon as a Negro comes into England, he becomes free.”[1]



Portugal declares that any African entering Portugal will be considered free (except for the Portuguese colony of Brazil).



Pope Benedict XIV issues a papal bull declaring the Catholic Church’s opposition to slavery in Brazil.



In Russia, Czar Peter III declares that one aspect of slavery is abolished.



Catherine the Great of Russia frees 900,000 peasants who reside on Church owned property.



Individuals in the Virginia House of Burgesses begin a boycott of the British slave trade.  They resolve that “they will not import any Slaves or purchase any imported, after the First day of November next, until the said [Tax] Acts of Parliament are repealed.”  Additional boycotts are started in South Carolina, North Carolina and Georgia.



Serfdom is abolished in the Kingdom of Savoy.

King Louis XV of France orders that individuals of African ancestry in the French colonies will be given the same rights as White citizens.



King Carlos III of Spain announces opposition to slavery.  Fugitive slaves seeking refuge in Spanish possessions will be given their freedom.  This does not, however, apply to the Spanish possessions in Latin and South America.

The Virginia House of Burgesses enacts a high tariff on slaves imported into the Colony, to limit slavery.  It writes King George II of England that “the importation of slaves into the colonies from the coast of Africa hath long been considered a trade of great inhumanity, and under its present encouragement, we have too much reason to fear will endanger the very existence of your Majesty’s American dominions.”  The proposed action is rejected by the Crown Government.



English Chief Justice, Lord Mansfield, rules against slavery in the “Sommersett Case.”  “The state of slavery is of such a nature, that it is incapable of being introduced on any reasons, moral or political, but only by positive law, which preserves its force long after the reasons, occasion, and time itself from whence it was created, is erased from memory.  It is so odious that nothing can be suffered to support it, but positive law.  Whatever inconveniences, therefore, may follow from the decision, I cannot say this case is allowed or approved by the law of England; and therefore the black must be discharged.”[2]  Slavery, however, remains legal in the North American colonies.

Portugal abolishes slavery within Portugal.



First Continental Congress is held.  Delegates Thomas Jefferson and Benjamin Franklin call for action of the delegates to end the importation of slaves by December 1, 1776.  This provision is put in the Articles of Association of the Continental Congress.


January 9, 1776

The Second Continental Congress passes resolution calling for end of the importation of slaves to America.  The resolution states that “no slaves be imported into any of the thirteen United Colonies.”


July 13, 1787

The United States Congress passes the Northwest Ordinance of 1787.  It outlaws slavery in the Northwest Territories, north of the Ohio River.



The French National Assembly orders the abolition of slavery in French colonial possessions.  In 1802, Napoleon reinstates slavery in the French colonies.



In England, the House of Commons approves resolution to abolish African slave trade, but House of Lords rejects it.


March 22, 1794

United States Congress passes law forbidding the slave trade to foreign ports.



Denmark becomes the first modern state to abolish the slave trade.



British Parliament approves resolution calling for the abolition of the slave trade.

Maryland, Massachusetts, New Hampshire, Ohio and Vermont submit resolutions to the U.S. Congress for an amendment to the constitution to end the slave trade.  Bills are presented in both houses calling for the end to the importation of slaves after December 31, 1807.


December 2, 1806

President Thomas Jefferson, in a message to the Congress, calls for a law criminalizing the international slave trade.  He asked Congress “to withdraw the citizens of the United States from all further participation in those violations of human rights…which the morality, the reputation, and the best of our country have long been eager to proscribe.”



United States Congress enacts law for the general abolition of slavery to take effect January 1, 1808.

Slave trade is declared illegal for British subjects.  The Act goes into effect in 1808 as the General Abolition Act.


March 2, 1807

President Jefferson signs the Act Prohibiting Importation of Slaves into law.  It takes effect on January 1, 1808.


January 1, 1808

The U.S. Congressional Act Prohibiting Importation of Slaves takes effect.  There are one million slaves residing in the United States.



British Colonial Government in India passes Abolition Act of 1811, which outlaws further importation of slaves to India.  Slavery will continue in India until it is prohibited in 1838.

British Parliament passes law making it a felony crime to participate in African slave trading.



Sweden abolishes its involvement in the African slave trade.


January 15, 1814

The Netherlands officially abolishes its involvement in the African slave trade.



European maritime nations attending Congress of Vienna issue proclamation condemning the African slave trade.



On return from exile, Napoleon Bonaparte, former emperor of France, announces abolition of the African slave trade.



France officially abolishes its involvement in the African slave trade.



The Spanish government abolishes its participation in the African slave trade in areas south of the Equator.



The Republic of Gran Columbia adopts policy of gradual abolition of slavery.

General José de San Martín outlaws African slave trade in Peru.  The government of Peru further enacts a law to begin abolition.



Britain signs treaty with Zanzibar to limit slave exports.



Chile outlaws slavery.



Gradual abolition of slavery begins in Argentina, Bolivia, Chile, Paraguay, and Peru.



Simón Bolívar drafts Constitution for Bolivia.  It officially abolishes slavery.



The government of Mexico abolishes slavery on September 15, 1829.  In December, however, it exempts Texas from the ban on slavery.



French and British diplomats negotiate a joint treaty to end African slave trade in international waters.

France bans French citizens from participating in the African slave trade.



British Parliament passes the Emancipation Act, which abolishes slavery in all its colonies.  By 1838, all slaves in the British colonies are freed.  The government provides slave owners in the West Indies with £20,000,000 in compensation for the abolition of slavery.



The Kingdom of Sardinia ends its participation in the African slave trade.

Jamaica and British Guyana abolish slavery.


August 28, 1833

An act calling for gradual, compensated abolition of slavery in the colonies is passed in the British Parliament.  United States anti-slavery groups are encouraged and highly motivated by this action.  American and English abolitionist groups will increasingly work together.



Mexico announces it will ban slavery in Texas, overturning an exemption made in 1829.



Portugal makes it illegal to export slaves from its colonies.



Hanseatic League of the Baltic Region outlaws its participation in the African slave trade.

The Kingdom of Tuscany outlaws its participation in the African slave trade.

Importation of slaves into Uruguay is banned.

Mexico passes new legislation abolishing slavery.  It calls for compensated emancipation.



By this date, slavery has been officially abolished in the British colonies.

India (Hindustan) officially abolishes slavery.

The Kingdom of Naples abolishes its participation in slavery.

Slavery is abolished in British Honduras (Belize).



British Parliament passes Palmerston Act, which authorizes British Naval vessels to inspect and intercept ships suspected of carrying slaves to the Americas.

Venezuela abolishes slave trade.

Pope Gregory XVI issues Papal Bull in Supremo, in which the Catholic Church condemns slavery and the slave trade.



Programs of gradual abolition are adopted in Colombia, Ecuador, and Venezuela.


June 12-23, 1840

The World Anti-Slavery Convention is held in London.  It refuses to admit women as delegates.  Numerous American abolitionists attend and many protest the exclusion of women.



Austria signs treaty with Great Britain, Prussia, France and Russia that outlaws its participation in the African slave trade.



Czar Nicholas I of Russia enacts law abolishing slavery.  Millions of Russians remain as impoverished serfs.

Paraguay begins process of abolishing slavery.



Indian government passes Act of 1843, abolishing legal status of slavery.

Great Britain and the United States enter into agreement to send Naval patrols to the west coast of Africa to prevent shipment of slaves.



Karl Marx and Friedrich Engels publish The Communist Manifesto, a call to workers to fight to end wage slavery.

France abolishes slavery in its colonies.



Ecuador and Columbia pass laws freeing all  their slaves.



Argentina, Venezuela, and Uruguay complete program of gradual abolition that began earlier.

Peru abolishes slavery under a policy of compensated emancipation.



Mexico adopts new Constitution.  It guarantees freedom for fugitive slaves arriving in Mexico.  Many U.S. slaves escape to Mexico until 1865.



The Dutch East Indies Colonial Administration abolishes slavery.


April 1861

Start of the Civil War in the United States.



United Kingdom issues Proclamation of Neutrality in the American Civil War.

Czar Alexander II of Russia issues degree freeing serfs.



Treaty signed between United States and Great Britain for the suppression of the slave trade (African Slave Trade Treaty Act).

Paraguay completes program of gradual emancipation that was started in 1825.


March 6, 1862

Abraham Lincoln sends message to the U.S. Congress proposing a plan of gradual, compensated emancipation.


April 1862

Law is passed by United States Congress providing for compensated emancipation of slaves in the District of Columbia.


April 10, 1862

United States Congress announces it will cooperate with any state in the gradual emancipation of its slaves.


September 1862

United States President Abraham Lincoln issues preliminary Emancipation Proclamation.



The Netherlands abolishes slavery in its colonies.


January 1, 1863

United States President Abraham Lincoln signs Emancipation Proclamation and it goes into effect, freeing slaves in states that have seceded and are part of the Confederacy.


January 31, 1865

The United States Congress passes the Thirteenth Amendment to the Constitution, abolishing slavery in the U.S.  By December 18, it becomes official.


April 1865

American Civil War ends.  Four million slaves are freed.



In the recently conquered region of Bukhara in Central Asia, the Russian government imposes abolition of slavery.



Spain enacts legislation to gradually abolish slavery in its colonies.



Slavery is ended in Puerto Rico.



Government of Siam (Thailand) begins reforms that begin the process of the abolition of slavery.



Government of Cambodia begins abolishing practice of slavery.  It officially ends slavery in 1884.

All slaves in Mozambique are liberated by order of Queen Victoria of England.



Spanish government passes Law of Patronato, which will eventually provide for gradual emancipation of slaves in Spanish possessions.



Korean government enacts policy to limit slavery to only one generation.  It abolishes hereditary slavery forever.



Pope Leo XIII issues Encyclical in support of enslaved peoples.

Slavery is ended in Brazil.



The Korean Choson (Yi) government abolishes slavery in Korea.



French government abolishes slavery in Madagascar.



The Ching (Quin) Imperial rulers in China decree the abolition of slavery in China.



Colonial administration of Malaya enacts law abolishing slavery.



Colonial administration of Burma enacts law abolishing slavery, beginning the process of compensated emancipation.

[1] Dumond, Dwight Lowell. Antislavery: The Crusade for Freedom in America. Ann Arbor, MI: University of Michigan Press, 1961, p. 5.

[2] Dumond, p. 5.


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