The breakthrough came when excavations at Morgantina (just south of Mt.
Etna in Sicily) found some fresh examples of only the earliest denarius issues in the destruction known to have occurred in 211 BC.
Pliny wrote (in the first century AD) that the denarius began five years before the first Punic War (in 268 BC), which seemed decisive for dating.
However, attempts at a complete chronology of early Republican coins made that date seem impossible.
Only a year or two later the successes in Sicily yielded booty from Syracuse (which was conquered in 212 BC -- famously the occasion when Archimedes was killed) to be converted into Roman coins.
Apparently the Romans took this occasion to introduce a new denomination, the denarius.
So the earliest denarius was from 211 BC or slightly before.
The earliest denarii have no legend referring to the moneyer (they are "anonymous." After about fifteen years moneyers began to sign their coins with monograms or longer abbreviations of their names).
Now we think his date was for the first silver Roman coins, but they were not denarii, rather didrachms in Greek style. "The moneyer is presumably a Pinarius Natta, not otherwise known" [Crawford, p. This event corresponds with the probable date of these coins." BMC does not mention this on page I. Scholars no longer think a revision of the calendar would make it onto coins, although 191 is not a highly improbable date.
246] The first "biga" issues have Luna or Diana driving the chariot (The illustrated one has Victory and is not the first). There is not really enough on the coin, and not enough hoard evidence, to pin down the date. There do not seem to be any coin types with a notable reference to the Third Punic War which resulted in the destruction of Carthage.
Some of the discussion about dating them would be clearer if the reader knew about the dating methodology called seriation which is explained on the theory page.
The dates given by Crawford in bold are, by far, the most quoted, and Sear quotes Crawford's dates, so the Sear dates are not repeated here. Reference works are listed at the bottom of this page. Wars put financial stress on states which we can sometimes see in the coinage.