ONE OF THE MOST frequently asked questions that classical numismatists encounter is "What was this ancient coin worth back then?"

A meaningful answer must usually begin: "It's complicated." A more complete answer might include "It depends..."

In our global economy, where almost everything is instantly convertible into cash, we can state precise exchange rates: one US dollar is worth 0.87 euro or 0.95 Swiss francs, or 0.65 British pounds. But what is today's value of a US dollar in terms of ancient Athenian drachmai, or ancient Roman sestertii? When an ancient Roman had a silver denarius in his purse, what could he buy with it? Ancient economies did not work like modern ones, and ancient writers, almost all slave-owning aristocrats who belonged to privileged elites, rarely wrote about the vulgar topic of money.

Bullion Equivalent Value
Ancient coins, like medals in the modern Olympic games, come in gold, silver and bronze. Can't we simply express equivalent ancient and modern values in terms of precious metal? Gold closed this week at US$1,142 per Troy ounce[4], so a 7.0-gram ancient Greek gold stater from the time of Alexander the Great (died 323 BCE) represents a bullion value of $262.87. An 8.18-gram Roman gold aureus from the time of Julius Caesar (died 44 BCE) would contain gold worth $307.18.

But "bullion equivalent value" is a very shaky basis for comparing buying power across the centuries. We are comparing gold that was mined with slave labor and refined in charcoal-fired furnaces to gold that is mined with huge diesel-powered shovels and refined with modern physical and chemical methods. In the ancient world, copper alloys (bronze and brass) formed tools, weapons, statues, cooking vessels and countless other non-coinage uses. In our world, copper is a commodity used mainly for electric wiring.

Labor Equivalent Value
We know from many sources that a silver drachma or denarius was a typical day's minimum wage for a manual worker. Taking today's US$7.25 minimum hourly wage for comparison, a day's labor would be worth $58. Keep in mind that when we compare labor equivalent values across the centuries, we are comparing an ancient world where muscle power was a primary energy source, to a modern world largely powered by engines, motors and data networks. In our world a small and diminishing number of farmers can each feed themselves and over 50 others. In the ancient world, most workers were farmers and they struggled to feed themselves and a few others.

Soldier's Pay
Another way of thinking about labor equivalent is soldier's pay - one of the most important items in the budget of ancient empires. In the fourth century BCE, Greek hoplites (armored infantry) typically received a drachma per day (sometimes supplemented by another drachma to pay for a servant while on campaign). Computed as an annual salary, this represents about 1,540 grams of silver or, converted into gold at the typical ancient 15:1 rate, 103 g of gold (about three-and-a-third troy ounces).

Now consider a modern soldier's pay. A US Army E-2 with less than two years service earns a base pay of $20,808. That would buy over 40 kilograms of silver, or about 555 grams (18.2 troy ounces) of gold at current rates. So in terms of the gold standard, Americans value a foot soldier more than five times as highly as ancient Greeks, and more than eight times as much as ancient Romans did.

Summary
Ancient economies were largely "bimetallic." Elites used gold coin, for purchases of luxury goods, property, and slaves. Silver coin typically circulated for the payment of wages, and bronze token coinage circulated for the purchase of daily necessities. At the risk of oversimplification, we can think of a small copper as the price of a loaf of bread, a pure silver coins as a worker's daily wage, and a gold coin as the price of a good horse.

Modern currency is primarily "fiat money", with a value determined by government, while ancient money was largely "commodity money", with values determined by the supply and demand of precious metals.

To read the complete article, see:
What Were They Worth? The Purchasing Power of Ancient Coins (www.coinweek.com/education/worth-purchasing-power-ancient-coins/)