Look up the history on coffee sometime. It was discovered in Kenya by a goat herder in the 7th century who noticed the goats eating the berries and getting peppy. So the locals tried it, liked it and began trading with their Arab neighbors. The Arabs liked it and decided the Kenyans who wouldn’t convert to Islam would make good slaves for the rest to pick the berries. And the rest, as they say, is history.
So why doesn't Saudi Arabia have a substantial Black population?
Because the muslim Saudis preferred their slaves castrated...