Most societies have exploited slave labour at some stage in their history. This is also true of Wales.
The transatlantic slave trade flourished from the early sixteenth century (about 500 years ago) until two hundred years ago when, in 1807, the British parliament passed an Act to abolish trading slaves within the British Empire.
Campaigns to stop slavery had been started by black and white people more than thirty years before the Act was finally passed. Even after 1807 the slaves already living in British colonies were not actually set free until 1838.
Slavery remained legal in some other countries for more than another fifty years. Today illegal slavery still continues in many parts of the world — even in Wales.