📖 Quick review
West Africa spans from modern-day Mauritania to the Democratic Republic of the Congo, mixing rainforests, savannas, and drier northern land. Most people lived away from the coast, connected to the interior by five main rivers: Senegal, Gambia, Niger, Volta, and Congo. After the death of Muhammad in 632 CE, Islam spread across North Africa, bringing a political and legal structure; Muslim armies instituted Islamic rule as local leaders converted, often under threat of death. The Ghana Empire grew rich by taxing trade, while Mali later became wealthy through new gold deposits and Muslim administration. Slavery existed in many forms, including bondage for protection, debt servitude, and evidence of chattel slavery; Muslim and later European slave trades expanded routes and demands. In the Americas, slavery became permanent and race-based, driven by the need for a permanent labor supply for plantation crops.