The maritime town of Lagos, Portugal, was the first slave market created in Portugal for the sale of imported African slaves, the "Mercado de Escravos", which opened in 1444. In 1441, the first slaves were brought to Portugal from northern Mauritania. Prince Henry the Navigator, major sponsor of the Portuguese African expeditions, as of any other merchandise, taxed one fifth of the selling price of the slaves imported to Portugal. By the year 1552 African slaves made up 10 percent of the population of Lisbon. In the second half of the 16th century, the Crown gave up the monopoly on slave trade and the focus of European trade in African slaves shifted from import to Europe to slave transports directly to tropical colonies in the Americas—in the case of Portugal, especially Brazil. In the 15th century, one-third of the slaves were resold to the African market in exchange of gold. Slavery was abolished in mainland Portugal and Portuguese India in 1761. It was finally abolished in all Portuguese colonies in 1869.