A siliqua is a smallish silver coin a little lighter than the classical denarius and about the same weight as an American Mercury head dime. It replaced the denarius (and an interim coin) after decades of economic, military, and political instabillity in the empire, around 300 AD. The first were introduced by Constantine the Great.

Constantine had four sons. The first, Crispus, was falsely implicated along with his mother (and the emperor's first wife) in treason, and executed. (Later it turned out that Constantine's second wife faked the evidence, and she joined them on the executioner's block.) His three son's by his second wife were Constantinus, Constantius, and Constans, in that order. They became co-Augusti on their father's death, and instantly fell on each other like hungry hyenas. They had inherited Constantine the Great's high character too, apparently...

Constantius II emerged the survivor, after having wiped out virtually the entire family, clan, and every imaginable supporter. Despite a suspicious and violent nature, Constantius was an able administrator, and the empire could spare a couple of hundred victims of royal rage and paranoia with ease. (Although the cost of cival war, and the lives of thousands of needed soldiers was something else.)

There was rather a lack of silver in the mid-4th century, or perhaps it was just that inflation had made it too expensive. Silver coins of this sort were struck, but in relatively small numbers compared to the early centuries of the empire. Or else there was a shortage of silver later, and most such coins were meted down a couple of centuries later. In either case, these are fairly hard to come by coins, and not cheap. I had all of three siliqua covering a hundred years, until I found this one.

One of the joys of collecting ancient coins is documenting them. It isn't enough to just have it, I want to know everything about it. Where was it minted, when, why? What does the inscription read? Why was it lost where it was? Who was paid it? What was it likely spent on? The answers to many of these questions can be found, though never all of course. I have never yet seen a coin with one possible exception, that had been in the hand of a man I could actually name. (But there was that one exception!)

The mystery to this siliqua of Constantius II's is the mint. According to what I had known about mint marks -- the letters at bottom of the right hand image -- this could have meant it was struck in Constantinople. PCON might have stood for Pecunia Constantinopolis. It was common for coins of this period to have mint marks preceded by M or SM, standing for Moneta and Sacra Moneta. But I have never actually seen Pecunia CON before, and it seemed suspicious in as much as the dealer's notes said it was minted in Arles. It took a bit of reading on Wikipedia to discover that for a period covering the mintng of this coin, Arles (France) had been renamed Constantina, after the emperor's wife. The abreviation used was for Pecunia, as surmised, but CON didn't stand for the imperial capitol, but for Arles! You can never know enough...