In many African religions, death is not seen as ending the life or personality of an individual, but merely as a change in a person's condition. Those who have died continue to live on in their community, communicating and helping their families as invisible but very real entities, the core of the African concept of ‘ancestors’. Over the centuries, seafarers of African descent serving in both British maritime services found themselves in a similar role to that of their own departed forebears in becoming an ‘unseen’ presence, at least in terms of being an often unacknowledged or unrecognized part of maritime life. Yet Black British sailors were there, revealed by the practised eye of the maritime artist in numerous paintings. Nineteenth-century artists such as Daniel Maclise, Denis Dichton and Andrew Morton show sailors of African descent engaged alongside their shipmates in the everyday shipboard toil, in a way that many historians do not. Nearer our own time in the history of black seafarers the camera has had the same facility, showing the reality of naval life as though a lens filter had been fitted that allows us to view an otherwise invisible presence. Just as Africans have traditionally believed that they could interact and communicate with their ancestors, so we can find seafarers of African descent on British ships in past centuries if we try. We do not have to try too hard.

Columbus's discovery of America in 1492 brought about the greatest expansion of Europeans into the rest of the world since the Vikings streamed out of their fjords seven centuries earlier. The resulting ‘White Diaspora’ in the newly discovered western lands was soon followed by a second, ‘Black Diaspora’, as the failure of both white and Native American slavery caused European settlers to look elsewhere for a labour force to work the land acquired from the indigenous peoples. Europeans looked to Africa as a new source of manpower, thus beginning a relationship between Africa and Europe that was far closer than any previously held.

The initial interaction between Africans and the British Navy was undoubtedly brought about by the slave trade, either directly or indirectly. The historian James Walvin argues that British involvement with black Africans does not date from the importation of black slaves into England and that an examination of the earlier and wider history of European explorations and discoveries is important.