I'm always trying to come up with a road map, trying to get a fairly exact location of where we're at in the historical continuum.
This lovely little dime-sized coin was minted in about 110 BCE, and shows the head of the goddess Roma, actually an adaptation of the winged-helmeted god Mercury. It's 90 percent silver (4-1/2 grams), a beautiful art miniature, and a day's wages for an unskilled laborer or a buck private in the army.
100 Years forward the republic of Roma is gone and the first emperor, Octavian Augustus, is on the throne and the denarius.
The coin, still very handsome, contains less silver than it's predecessor -- 3.9 grams. It theoretically conveyed the same value as before, but was objectively worth less.
Fast forward another 100 years and it's the year 200 of the Current Era, or Anno Domini if you prefer. Old Septimius Severus, the severe one, he whom Edward Gibbon labeled "the principal author of the decline of the Roman Empire" sits atop the colossal heap. His denarius is artistically impressive as the others, but its silver content was reduced by Nero, and is now somewhere between 3 and 3.4 grams.
By 270 CE when Claudius Gothicus was fighting and beating the Goths, the denarius was a ghost of its former self. As you can see from its color, this is essentially a copper coin -- a kind of shrunk-up penny with a little silver in it. However, it's worth pointing out that the portrait shows the quality of Roman monumental portraiture remaining quite high, even at this late date. I like the portrait of this tough, dedicated general with his spiky war hat, as well or better than any minted since the Republic.
So, what's in your wallet?