Salt was an international currency
It was traded like money. Since currencies in different countries have always differed, salt was an international currency. It was an important trading commodity carried by explorers. Greece, involved in a far-reaching slave trade, exchanged salt for slaves, giving rise to the expression “worth his salt.”
Special salt rations given to roman soldiers along with their wages known a solarium argentums, the term from which our word “salary” is derived. In Venice, the immense salt evaporation pans were referred to as “the Seven Seas.” The phrase “sailing the Seven Seas” derived from the challenge of navigating one’s craft among the bars that enclosed these evaporation ponds.
Salt was traditionally expensive, and used to bestow social standing. Salt has played a prominent role in religious ritual in many cultures, symbolizing purity. There a more than 30 references to salt in the Bible. “Salt of the Earth” was an expression given to Lot’s wife, and given the expense of salt in early times, being turned into a pillar of great value.
Throughout history the need for salt has made it easy for governments to monopolize and tax it. This has resulted in much political turmoil. Salt taxes often supported a major share of national budgets. From one Chinese dynasty to the next, China’s emperors filled their coffers with high taxes levied on the salt industry they monopolized. Profits from the sale of salt financed the Great wall. French kings developed a salt monopoly by selling exclusive rights to produce it to a favored few, who exploited that right to the point where the scarcity of salt was a major cause of the French revolution.
Salt taxes long supported British monarchs. And Mahatma Gandhi’s challenge to colonial Britain’s salt tax in India was the pre-eminent act of civil disobedience that rallied his countrymen to demand and achieve independence.