Corpus of Early Arabic Sources for West African History - Google Books

http://books.google.de/books?id=L3tNlgQmT9wC&printsec=frontcover&dq=levtzion+corpus&hl=de&ei=hskOTraIHcnUsgbm2ajbCw&sa=X&oi=book

From the eighth century onwards, the Muslim townsfolk of North Africa were well aware that fifty stages away across the desert to the south lay a land inhabited by black people which was the source of gold, ivory and slaves. It was no mere rumor stemming…