Francisco Rolão Preto was a Portuguese explorer who lived in the late 1300s. He was the first European to explore the coast of West Africa, which includes countries like Ghana, Guinea, and Sierra Leone. He sailed down the coast, seeking new lands and trading goods to bring back to Portugal. He also brought many African slaves back to Portugal to work in their colonies. By exploring the coast of West Africa, he found many things that helped the Portuguese people learn more about the world.