I like them too. I have a few but have always meant to get more. To me, they are interesting because it shows what was important on a coin, much like Celtic copies of coins do. The celators concentrated on what the essence of a "coin" meant to illiterate people who used them, and in that light I find them fascinating.
A radiate is another term for the double denarius that was started in early 200's. The denari had been debased, so they made a new denomination of a double denari, or radiate, or antininous. "Radiate" comes from the radiate crown the emperor wears on them to differentiate them from denari.
The correct term for these is really "contemporary imitations," as they were struck within the Empire. I have a small collection of imitations and contemporary counterfeits: http://www.forumancientcoins.com/gallery/thumbnails.php?album=1602
Just curious. How do we know they were struck within the empire and are not limes coins? I thought there were reports of Roman currency circulating amongst the German tribes at the time, procured either from trade or plunder.
I think barbarous is a broad term- meaning coins made when there was a need for coinage imitating another coin type. Here are a couple more interesting barbs. the first one was a metal detector find in the Uk and i havent been able to find too many examples of its an imitation of CONSTANTI-NVS MAX AVG, laureate head rightSPES PVBLICA across field, labarum, with three medallions on drapery and crowned by a christogram, spearing serpent. CONS in exergue. RIC VII 19. According to RIC, this famous reverse type represents the defeat of tyranny by the death of Licinius. Yet, the scene also has powerful Christian imagery in that it allegorically portrays the power of Christianity over evil. The second coin is in over strike or double strike.
I dont really know yet if it is official or a barb I just labeled it as a barb because I could only find a barb coin that was this size and weight. To tell the truth it has very good engraving on the coin and the letters where almost perfect looking and not barbarous at all before I tried to clean it which I wish I never did but it looked like just another low grade coin. I wasnt expecting this at all it was a pleasant suprise and at the same time a regret that I had cleaned it so harshly.
I would say that Spes should be sent out to a professional cleaner/restorer. Those are indeed special coins.