Historically, dietary salt (sodium chloride) has been obtained by numerous methods, including solar evaporation of seawater, the boiling down of water from brine springs, and the mining of “rock” salt (Brisay and Evans 1975). In fact, R. P. Multhauf (1978) has pointed out that “salt-making” in history could be regarded as a quasi-agricultural occupation, as seen in frequent references to the annual production as a “harvest.” Such an occupation was seasonal, beginning with the advent of warm weather or the spring high tide and ceasing with the onset of autumnal rains. Multhauf has argued further that the quest for salt led to the development of major trade routes in the ancient world. The historian Herodotus, for example, described caravans heading for the salt oases of Libya, and great caravan routes also stretched across the Sahara, as salt from the desert was an important commodity exchanged for West African gold and slaves. Similarly huge salt deposits were mined in northern India before the time of Alexander the Great, and in the pre-Columbian Americas, the Maya and Aztecs traded salt that was employed in food, in medicines, and as an accessory in religious rituals. In China, evidence of salt mining dates from as early as 2000 B.C.

Homer termed salt “divine,” and Plato referred to it as “a substance dear to the gods.” Aristotle wrote that many regarded a brine or salt spring as a gift from the gods. In the Bible (Num. 18: 19), it is written: “This is a perpetual covenant of salt before the Lord with you and your descendants also.” In the Orient, salt was regarded as the symbol of a bond between parties eating together. In Iran, “unfaithful to salt” referred to ungrateful or disloyal individuals. The English word “salary” is derived from salarium, the Latin word for salt, which was the pay of Roman soldiers. Moreover, Roman sausages were called salsus because so much salt was used to make them (Abrams 1983).