Portugal and Spain Portugal was the first European country to trade in slaves from Africa, initially mainly to bring them back to Portugal (there were 32,000 African slaves in Portugal in the 16th century, working mainly in the fields and sugar plantations).ome, such as England, France and Portugal used slave labour in their colonies while others, such as the Netherlands, Norway and Denmark, were mainly active in the commercial trade and shipping, thus contributing to the trade by carrying slaves from Africa to the Caribbean and Latin America.