The “triangular trade” of the 18th century was a substantial component of the economy of Britain, its West Indian possessions and its American colonies, though it came at the horrible expense of enslaving untold numbers of Africans.

The original of this portrait of Thomas Clarkson by Carl Frederik von Breda hangs in the National Portrait Gallery in London.

This marker along a road near London commemorates the spot where, in 1785, an anguished Clarkson dismounted his horse, fell to his knees and resolved to commit his life to the antislavery cause.

Short in stature and in ill health for much of his life, William Wilberforce, the antislavery movement’s best friend in Parliament, is remembered today as a great orator and a towering figure in British history.

Clarkson's slave ship diagram proved immensely valuable as a visual tool. The image of hundreds of human beings crammed together in unimaginably appalling conditions stirred the conscience of people everywhere.

The great pottery entrepreneur Josiah Wedgwood, a Clarkson ally, commissioned the creation of this image. "Am I Not A Man And A Brother?" appeared on medallions and plates and in many other media to powerful effect.