Final answer:
Portuguese sailors began to explore and map the African coastline under Prince Henry the Navigator, establishing trading posts to facilitate the trade of gold and slaves.
Step-by-step explanation:
Under the orders of Prince Henry the Navigator, Portuguese sailors began to explore and map the African coastline. These explorations were conducted not only to chart unknown territories but also to establish trading posts along the coast. Such establishments were crucial for the trade of gold, and later, facilitated the deplorable trade of enslaved individuals to Europe.
As they ventured further along the West African coast, they would secure gold, forge alliances with African leaders, and set up feitorias (fortresses) that functioned as trading ports and holding areas for slaves. This laid the groundwork for Portugal's vast trade empire during the fifteenth and sixteenth centuries and the emergence of the Trans-Atlantic slave trade driven by the demand for labor-intensive crops.