Silent Trade is a method by which people with no common language could barter goods. Group A would leave trade goods in a prominent position and signal, by gong, fire, or drum for example, that they had done so. Group B would then arrive at the spot, examine the goods and deposit their trade goods that they wanted to exchange and withdraw. Group A would then return and either accept the trade by taking the goods from Group B or withdraw again leaving Group B to add to or change out items to create an equal value. The trade ends when Group A accepts Group B's offer and removes the offered goods leaving Group B to remove the original goods.

The practice was certainly well established between tribes in Africa in their trade with India. Cosmas Indicopleustes describes this practiced in Azania, where officials from Axum bartered for gold with beef ¹. Prince Henry the Navigator of Portugal recorded this practice when he occupied Ceuta in 1415.

Notes

1. Cited in J. Innes Miller, The Spice Trade of the Roman Empire (Oxford: Univeristy Press, 1969), pp. 167f. Although Miller offers an extensive passage in translation, he does not provide the source for his quotation.