The slave trade increasingly became Kongo's primary, and arguably sole, economic sector. A major obstacle for the Kingdom of Kongo was that slaves were the only commodity for which the European powers were willing to trade. Kongo lacked an effective international currency. Kongolese nobles could buy slaves with the national currency of nzimbu shells, which could be traded for slaves. These could be sold to gain international currency.
The slave trade increasingly became Kongo's primary, and arguably sole, economic sector. A major obstacle for the Kingdom of Kongo was that slaves were the only commodity for which the European powers were willing to trade. Kongo lacked an effective international currency. Kongolese nobles could buy slaves with the national currency of nzimbu shells, which could be traded for slaves These could be sold to gain international currency.