Johnson’s lifetime coincided almost exactly with the rise and fall of the British slave trade. Some Britons had been involved in slave trading as early as the sixteenth century, but for most of the sixteenth and seventeenth centuries Great Britain was a relatively minor participant. Britain signaled its intention to make serious money from slave trading with the establishment of the Royal Adventurers into Africa in 1660. This company, which genuinely was led by members of the restored royal family, shortly after became the Royal African Company.

The asiento

It was not until the early eighteenth century, however, that Britain wrested control of the slave trade from the Spanish, who had dominated slave trading throughout the seventeenth century. The turning point was the War of the Spanish Succession (1701–14). On the face of it this was a dynastic conflict, which contemporaries knew would determine the balance of power in Europe, but in the event it would also determine the relationship between Europe, Africa, and the New World for the rest of the eighteenth century and, arguably, for much longer. The war was concluded with the Peace of Utrecht (1713). As part of the negotiations towards this treaty, Spain granted Britain the right to supply its colonies in the New World with slaves, an agreement known as the asiento. From this point onwards, Britain became the foremost slave-trading nation, a position it continued to occupy until it voluntarily abolished its slave trade in 1807.