# How could the Roman sestertii/sesterces be converted into modern terms (say 2017 US\$)?

Of course, the value of the sesterti must itself have fluctuated over the centuries it was in use. And so if I must narrow it down, I am particularly interested in its value during

• the time of Lollia Paulina who was once covered with 40M sesterces' worth of jewels; and
• the time of Cleopatra, who once drank a dissolved pearl worth 10M sesterces,

both of these stories being from Pliny, Book 9, Ch. 58.

Adam Smith writes in The Wealth of Nations:

When we read in Pliny, therefore, that Seius bought a white nightingale, as a present for the Empress Agrippina, at a price of six thousand sestertii, equal to about fifty pounds of our present money; and that Asinius Celer purchased a surmullet at the price of eight thousand sestertii, equal to about sixty-six pounds thirteen shillings and fourpence of our present money

Smith also writes:

Three sestertii, equal to about sixpence sterling,

which would be consistent with the previous quote, since £1 = 240p.

So according to Smith, 6,000 sestertii ≈ £50 "of our present money". The Wealth of Nations was first published in 1776. Using the Bank of England's inflation calculator, £50 in 1776 = £7,519.57 in 2016, or about US\$10,000 at current conversion rates (according to Google).

So 6,000 sestertii ≈ US\$10,000 in 2017 or 1 sesterti ≈ US\$1.67? Thus

• Lollia Paulina's jewels (40M sesterces according to Pliny) would be worth US\$66.7M today? And
• Cleopatra's swallowed pearl (10M sesterces according to Pliny) would be worth US\$16.7M today?

Of course, I have no idea how Adam Smith did his conversion, but presumably some modern day historians/economic historians have since done better.

• Possible duplicate of How can prices be compared over time? – CsBalazsHungary Nov 23 '17 at 10:18
• @CsBalazsHungary: That is a broad methodological question. This is a specific question about a specific currency at a specific time in history. – Kenny LJ Nov 23 '17 at 11:27
• I am afraid you will get only estimations like in the other question, the difference will be big in time, I am sure Adam Smith used his estimation which is more or less accurate. It is easier to convert his USD to modern day USD, but keep in mind how different is the world now than in Adam Smith's time or roman time. It is not just different monetary system, very different basket of goods are bought for the currencies we use today. – CsBalazsHungary Nov 23 '17 at 12:00
• by coin materials weight to price ratio? that's how it went back then. – CptEric Nov 23 '17 at 14:39
• There is no meaningful way to compare prices across time and history. The Bureau of Labor and Statistics struggles to compare them across decades – Mark C. Wallace Nov 23 '17 at 21:07

Value of money is not the same as in Ancient Times. Today, we use fiat currency, and use it for absolutely everything.

At those times, money was a commodity currency and quite scarce; trade by goods was more common than trade by currency. Not to mention that needs were very different (hence the value of those needs was different as well) and products that nowadays are common and cheap could be really expensive at that time, so it's very difficult to do a direct translation of prices.

But if we use the commodity approach just as if we were in Roman Empire and we have that:

From Sestertius

the silver sestertius valued at two and one-half grams. In practice, the coins were usually underweight.

Silver Price per Gram \$0.55

then...

``````2.5*0.55=1.375
``````

which is pretty close to your figures, and somehow logical, because it's a commodity currency.

So now let's go to the values...

Lollia Paullina jewels: `40,000,000*1.375=55,000,000 dollars`

Cleopatra's pearl: `10,000,000*1.375=13,750,000 dollars`