Before the second half of the seventeenth century, in each of the countries under discussion, the number of slaves coming from other countries was negligent, if not almost non-existent in the case of England.

All that changed in the period 1650–1800. In this era, the European powers made massive use of slave labour in their colonies. Slavery was considered to be legal in the colonies, as we confirmed through our survey of both international law and colonial slave laws between the sixteenth-eighteenth centuries. Especially towards the end of this period, colonial proprietors living in the English, French and Dutch colonies often returned to their respective metropolises and took one or more slaves with them. Likewise, slaves sometimes managed to make it to the motherland by themselves or ended up there in one or another way. What does a comparison of the behaviour of metropolitan courts and legislators, as well as the reality “on the ground” teach us?