<Table> <Tr> <Td> </Td> <Td> This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations . Please help to improve this article by introducing more precise citations . (October 2010) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations . Please help to improve this article by introducing more precise citations . (October 2010) (Learn how and when to remove this template message) </Td> </Tr> <P> Antão Gonçalves was a 15th - century Portuguese explorer and slave trader who was the first European to buy Africans as slaves from black slave traders . </P>

In what year did the portuguese explorer return some slaves to lisbon