On Thursday 28 November 1771, a ship called the Ann and Mary was moored in the Thames ready to leave for the West Indies with its cargo. That cargo had a name that would reverberate in English legal history for the case that bore it and for the ruling that concluded that case, known simply to posterity as the Mansfield Judgment.

The cargo had been a domestic slave and had been given the name James Somerset by his white owner, a Virginia trader aptly called Charles Stuart. Stuart came over to England and of course, along with a lot of other items of domestic property, brought his slave with him. He was a valuable piece of property worth some £50. Somerset managed to escape and lose himself among the several thousand blacks who already lived in London. Slave catchers, however, were put on his track and he was captured, shackled and put on board the Ann and Mary to be taken to Jamaica and sold into plantation work. This was not done in secret, the law was not being evaded. An owner had lost his property, given a reward for it being found, and now wanted to dispose of it at his will, as he would have done of a lost ring or a pig that had escaped its enclosure.