1787 - The Society for Effecting the Abolition of the Slave Trade founded in Great Britain

The Society for Effecting the Abolition of the Slave Trade (or The Society for the Abolition of the Slave Trade), was a British abolitionist group, formed on 22 May 1787, by twelve men who gathered together at a printing shop in London. The Society worked to educate the public about the abuses of the slave trade; it achieved abolition of the international slave trade in 1807, enforced by the Royal Navy. The United States also prohibited the African slave trade that year, to take effect in 1808.


Nine of the twelve founding members of the Society for Effecting the Abolition of the Slave Trade were Quakers: John Barton (1755–1789); William Dillwyn (1743–1824); George Harrison (1747–1827); Samuel Hoare Jr (1751–1825); Joseph Hooper (1732–1789); John Lloyd; Joseph Woods Sr (1738–1812); James Phillips (1745–1799); and Richard Phillips. Five of the Quakers had been amongst the informal group of six Quakers who had pioneered the movement in 1783, when the first petition against the slave trade was presented to parliament.

The first anti-slavery statement was written by Dutch and German Quakers, who met at Germantown, Pennsylvania in 1688. English Quakers began to express their official disapproval of the slave trade in 1727 and promote reforms. From the 1750s, a number of Quakers in Britain's American colonies also began to oppose slavery, and called on English Quakers to take action with parliament. They encouraged their fellow citizens, including Quaker slave owners, to improve conditions for slaves, educate their slaves in Christianity, reading and writing, and gradually emancipate (free) them.

And so it was that an informal group of six Quakers pioneered the British abolitionist movement in 1783 when the London Society of Friends' yearly meeting presented its petition against the slave trade to Parliament, signed by over 300 Quakers. They were also influenced by publicity that year about the Zong massacre, as the ship owners were litigating a claim for insurance against losses due to more than 132 slaves having been killed on their ship.

The Zong massacre was the mass killing of 133 African slaves by the crew of the British slave ship Zong in the days following 29 November 1781. The Gregson slave-trading syndicate, based in Liverpool, owned the ship and sailed her in the Atlantic slave trade. As was common business practice, they had taken out insurance on the lives of the slaves as cargo. When the ship ran low on potable water following navigational mistakes, the crew threw slaves overboard into the sea to drown, partly in order to ensure the survival of the rest of the ship's passengers, and in part to cash in on the insurance on the slaves, thus not losing money on the slaves who would have died from the lack of drinking water.

After the slave ship reached port at Black River, Jamaica, Zong's owners made a claim to their insurers for the loss of the slaves. When the insurers refused to pay, the resulting court cases (Gregson v Gilbert (1783) 3 Doug. KB 232) held that in some circumstances, the deliberate killing of slaves was legal and that insurers could be required to pay for the slaves' deaths. The judge, Lord Chief Justice, the Earl of Mansfield, ruled against the syndicate owners in this case, due to new evidence being introduced suggesting the captain and crew were at fault.

Following the first trial, freed slave Olaudah Equiano brought news of the massacre to the attention of the anti-slavery campaigner Granville Sharp, who worked unsuccessfully to have the ship's crew prosecuted for murder. Because of the legal dispute, reports of the massacre received increased publicity, stimulating the abolitionist movement in the late 18th and early 19th centuries; the Zong events were increasingly cited as a powerful symbol of the horrors of the Middle Passage of slaves to the New World.

On a subsequent application to set that judgment aside, Lord Mansfield indicated that the jury in the initial trial; 

"had no doubt (though it shocks one very much) that the Case of Slaves was the same as if Horses had been thrown over board ... ". 

That finding was overturned and fresh trial ordered, but in both legal actions it was accepted in principle by the court that the killing of the negro slaves was permissible, and did not thereby invalidate the insurance by virtue of being an unlawful act. Shortly afterwards provisions in the Slave Trade Act 1788 made it unlawful to insure against similar losses of slaves.

The Slave Ship, originally titled Slavers Throwing overboard the Dead and Dying—Typhoon coming on, is a painting by the British artist J. M. W. Turner, first exhibited in 1840 and now in the Museum of Fine Arts, Boston. 

In this classic example of a Romantic maritime painting, Turner depicts a ship, visible in the background, sailing through a tumultuous sea of churning water and leaving scattered human forms floating in its wake.

J.M.W. Turner was inspired to paint The Slave Ship in 1840 after reading The History and Abolition of the Slave Trade by Thomas Clarkson.

This event probably inspired Turner to create his landscape and to choose to coincide its exhibition with a meeting of the British Anti-Slavery Society. Although slavery had been outlawed in the British Empire since 1833, Turner and many other abolitionists believed that slavery should be outlawed around the world. Turner thus exhibited his painting during the anti-slavery conference, intending for Prince Albert, who was speaking at the event, to see it and be moved to increase British anti-slavery efforts. Placed next to the painting were lines from Turner's own untitled poem, written in 1812:

        "Aloft all hands, strike the top-masts and belay;
        Yon angry setting sun and fierce-edged clouds
        Declare the Typhon's coming.
        Before it sweeps your decks, throw overboard
        The dead and dying – ne'er heed their chains
        Hope, Hope, fallacious Hope!
        Where is thy market now?"

The art critic John Ruskin, who was the first owner of The Slave Ship, wrote; 

"If I were reduced to rest Turner's immortality upon any single work, I should choose this."

The painting was the subject of an extended poetic sequence or verse novel by David Dabydeen, Turner (1994; reissued 2002).

"Turner" is a long narrative poem written in response to J. M. W. Turner s celebrated poem Slavers Throwing Overboard the Dead and Dying. Dabydeen s poem focuses on what is hidden in Turner s painting, the submerged head of the drowning African. In inventing a biography and the drowned man s unspoken desires, the poem brings into confrontation the wish for renewal and the inescapable stains of history, including the meaning of Turner's painting.








Three Anglicans were founding members: Philip Sansom;  Thomas Clarkson, campaigner and author of an influential essay against the slave trade; Granville Sharp who, as a lawyer, had long been involved in the support and prosecution of cases on behalf of enslaved Africans and was directly involved with the Zong massacre case.

Sharp was visited on 19 March 1783 by Olaudah Equiano, a famous freed slave and later to be the author of a successful autobiography, who told him of the horrific events aboard the Zong. Sharp immediately became involved in the court case, facing his old adversary over slave trade matters, the Solicitor General for England and Wales, Mr. John Lee. Lee notoriously declared that "the case was the same as if assets had been thrown overboard", and that a master could drown slaves without "a surmise of impropriety".

The judge ruled that the Zong's owners could not claim insurance on the slaves: the lack of sufficient water demonstrated that the cargo had been badly managed. However, no officers or crew were charged or prosecuted for the deliberate killing of the slaves, and Sharp's attempts to mount a prosecution for murder never got off the ground.

Josiah Wedgwood was a prominent slavery abolitionist. His friendship with Thomas Clarkson – abolitionist campaigner and the first historian of the British abolition movement – aroused his interest in slavery. 

Wedgwood mass-produced cameos depicting the seal for the Society for Effecting the Abolition of the Slave Trade and had them widely distributed, which thereby became a popular and celebrated image. The Wedgwood medallion was the most famous image of a black person in all of 18th-century art.


From 1787 until his death in 1795, Wedgwood actively participated in the abolition of slavery cause. His Slave Medallion brought public attention to abolition. Wedgwood reproduced the design in a cameo with the black figure against a white background and donated hundreds to the society for distribution. Thomas Clarkson wrote; "ladies wore them in bracelets, and others had them fitted up in an ornamental manner as pins for their hair. At length the taste for wearing them became general, and thus fashion, which usually confines itself to worthless things, was seen for once in the honorable office of promoting the cause of justice, humanity and freedom".

The design of the cameo was probably done by either William Hackwood or Henry Webber who were modellers in his Stoke-on-Trent factory. The design on the medallion became popular and was used elsewhere: large-scale copies were painted to hang on walls and it was used on clay tobacco pipes.

Thomas Clarkson, as a leading English abolitionist, and a leading campaigner against the slave trade in the British Empire, began his campaigning after publishing in pamphlet form his prize winning essay on 1786 - An essay on the slavery and commerce of the human species, particularly the African, translated from a Latin Dissertation.

The essay was influential, and led to Clarkson being introduced to many others who were sympathetic to abolition, some of whom had already published and campaigned against slavery. Encouraged by publication of Clarkson's essay, an informal committee was set up between small groups from the petitioning Quakers, Clarkson and others, with the goal of lobbying Members of Parliament. This led in turn to the forming of the Committee for the Abolition of the Slave Trade. The Committee included Granville Sharp as Chairman and Josiah Wedgwood, as well as Clarkson. Clarkson also approached the young William Wilberforce, who as an Anglican and an MP was connected within the British Parliament. Wilberforce was one of few parliamentarians to have had sympathy with the Quaker petition; he had already put a question about the slave trade before the House of Commons, and became known as one of the earliest Anglican abolitionists.

It was Clarkson who took a leading part in the affairs of the Committee for the Abolition of the Slave Trade, and was tasked to collect evidence to support the abolition of the slave trade. He faced much opposition from supporters of the trade in some of the cities he visited. The slave traders were an influential group because the trade was a legitimate and highly lucrative business, generating prosperity for many of the ports.

Liverpool was a major base of slave trading syndicates and home port for their ships. 

In 1787, Clarkson was attacked and nearly killed when visiting the city, as a gang of sailors was paid to assassinate him. He barely escaped with his life. 

Elsewhere, however, he gathered support. Clarkson's speech at the collegiate church in Manchester (now Manchester Cathedral) on 28 October 1787 galvanized the anti-slavery campaign in the city. That same year, Clarkson published the pamphlet A Summary View of the Slave Trade and of the Probable Consequences of Its Abolition.

Clarkson attempted to show that the slave trade was highly dangerous. He claimed that of 5,000 sailors on the triangular route in 1786, 2,320 came home, 1,130 died, 80 were discharged in Africa and unaccounted for and 1,470 were discharged or deserted in the West Indies.  

Clarkson claimed that in Liverpool alone, over 15,165 seaman had been lost since 1771 in the 1,001 ships that had sailed from there to the coast of Africa.