For much of the ancient world, salt was a signifier of wealth. In Africa it was traded with merchants in exchange for gold. It was used as a form of currency, to pay for goods and sometimes for slaves. This is not just ancient history, by the way. During the Second World War, as Nigeria faced shortages and the threat of famine, salt was used as a currency in many of the villages in the north, with British salt fetching the highest exchange rate.
