Behold under what circumstances it was established: The Mussulmans, after being expelled from Spain, took refuge beyond the Strait on the coast of Africa.

The Portuguese, who then occupied that part of the coast, pursued them with fury.

A certain number of those fugitives were made prisoners and brought back to Portugal.
Reduced to slavery, they constituted the first nucleus of African slaves which has been formed in Western Europe since the Christian Era.
But those Mussulmans belonged, for the most part, to rich families, who wished to buy them back for gold.

The Portuguese refused to accept a ransom, however large it might be.

They had only to make foreign gold.