Prince Henry established a slave market and fort in Arguin Bay (West Africa) in 1445 and the enslaved Africans were brought back to Portugal. When a large slave auction was held in Lagos (Portugal) in that same year it was described by one witness as a "terrible scene of misery and disorder". By 1455, Eight-hundred Africans were transported to Portugal annually.
By the 1470s Lisbon, Portugal's capital city, became the country's main slave port. The Portuguese slave trade started then not as a trans-Atlantic trade but as an old world trade, supplying slaves to Lisbon and hence onwards to Spain and Italy. In 1539, twelve thousand African slaves were sold in the city's markets. This differed from other European countries' experience of the trade which developed much more in their colonies.
Lisbon also thrived off the businesses associated with slavery, with Portuguese goods exchanged for slaves, goods traded for slaves and goods produced by the slaves. People invested in the trade, and profited, and the Royal family took its share through taxation. African slaves were employed in a variety of occupations but increasingly they were to be found in urban employment such as domestic service.
Old Slave Market, Lagos, Portugal
In one corner of The Praca da Republica, under the arches of the old customs house is what was Europes first Slave Market. (mercado de escravos). The market opened in 1444 and it is said that within a hundred years up to 10,000 slaves were being shipped from Africa every year just to meet Portugusese demand alone. the customs House now serves as an art Gallery. (source:http://members.virtualtourist.com/m/p/m/1b2a0b/#ixzz1pxQnp3Au)
Formerly a custom house, the Antigo Mercado de Escravos, today, serves as a stark reminder of the arcade slave market which was housed inside this Romanesque structure during the Age of Exploration. The monument is located on the main square of the historic part of the city and is, perhaps, one of a kind custom house in Europe.