It is said that Ghana obtained its gold by “silent” or “dumb” barter which was described as follows

The writer of the above lines (E. W. Bovill), a supposed European authority on the Western Sudan, then goes on to say that silent trade or dumb barter was a feature of the Western Sudan’s gold trade throughout all the centuries until modern times. Actually, the only thing dumb about the trade is what he writes about it. The story of dumb barter for gold in West Africa is repeated in several accounts, starting with ancient Greek scripts. It is clearly a rough approximation of the first attempts at exchange of a people coming into contact with strangers, and it was not a permanent procedure.

p. 57