Portugal established settlements along the coast of Africa beginning in 1531, controlling coastal territories into the 20th century. In the 16th century, Portugal began the European slave trade, shipping over one million men, women and children from territories in Guinea and Angola across the Atlantic. While Britain attempted to gain a foothold in Africa in the late 18th century, Portuguese coastal territories remained dominant into the 19th century, largely due to the profitable slave trade along the Angolan and Guinean coasts.