What’s a civilization in Africa and Asia largely because of increased trade during the medieval period?

West Africa was one of the world's greatest producers of gold in the Middle Ages. Trade in the metal went back to antiquity but when the camel caravans of the Sahara linked North Africa to the savannah interior, the trade really took off. A succession of great African empires rose off the back of the gold trade as salt, ivory, and slaves were just some of the commodities exchanged for the precious metal that eventually found its way into most of southern Europe's gold coinage. Gold attracted unwanted attention and competition, too, with the Portuguese the first to exploit West Africa's coastal resources from the 15th century CE, and in their wake followed others. The discovery of the Americas and the gold of the Aztecs and Incas only gave West Africa a temporary respite as European colonial powers then returned to the continent as their chief source of slaves to work on the plantations of the New World. The trade of gold in West Africa goes back to antiquity with one of the earliest examples being the voyage of the Carthaginian explorer Hanno in the 5th century BCE. The celebrated mariner sailed out of the Mediterranean and, turning south, stopped off at the mouth of the Senegal River before sailing on and perhaps even reaching as far the Bay of Guinea. Hanno was followed by other countrymen, and commercial relations were established with the locals. Thus, West African gold found its way from the trading post/island of Cerne (unidentified but on the Atlantic coast) northwards to the ancient Mediterranean cultures for the first time.
The 5th-century BCE Greek historian Herodotus describes in his Histories that gold was traded on the West African coast using a silent and cautious method of barter - perhaps understandable given the language barrier and mutual fear between unfamiliar peoples. Hope this helps! Mark please!