Dealer that offered this coin says it's Procopius for sure. I could have sworn I saw this reverse type for Constantius II but I'm not finding it. I just want to make sure it's a unique type and not shared by other emperors. Here is the attribution as Procopius. Procopius AE3. OBV: DN PROCOPIVS P F AVG, Pearl diademed, draped bust right. REV: SECVRITAS REIPVB, Emperor standing left, head right, holding labarum & shield on ground. REF: Waage 1764cf, Not in RIC.
I only have one and it was 'found' among a lot of 'uncleaned' coins, so the grade is about Fine and hard to photograph ...but for comparison, here it is:
For this period RIC is old (1933). Your Procopius type was unknown at the time. Numerous examples, almost all in terrible or mediocre shape, have appeared since the 1990s. See type 8A on my educational page: http://esty.ancients.info/ricix/ I still consider it rare and highly desirable.
If it is Procopius (and I would buy it as such), Obverse legend should be DN PROCOPIUS PF AVG and the Reverse Legend SECVRITAS REIPVB with CONS in ex. If you check 'Wildwinds' under Procopius / Constantinople you might find it.
One of Constantius II 'Reverses' has 'Constantius' standing left, holding labarum and resting hand on shield. Perhaps that is what you saw? Procopious is standing 'facing'. (See Acsearch)
Your coin is no doubt Procopius with SECVRITAS REIPVB reverse. They used to be very rare, unlisted in both RIC and Cohen but nowadays downgrade to about scarce to at best rare in better condition. Curtis Clay notes on this type: "Though not in Cohen or RIC, specimens of this coin have been emerging in recent years: the first published in 1977, one in BM, one in the current Berk catalogue 142, lot 345, and now these two. [noted in feb. 2005, at least 10 others known from then on.] See commentary to Berk coin below, which I wrote in ignorance of the Wildwinds specimen, which is incidentally from a new officina, delta or A rather than E. The very rare earliest issue of Procopius' bronze coinage, not only continuing Valentinian's reduced weight standard and copying his right-facing portrait, but also taking over Valentinian's reverse legend SECVRITAS REIPVB, combined with Procopius' normal type of emperor standing. Only two specimens of this coin seem to have been recorded until now: that published by W. Weiser in Money trend 1977, pp. 8-12, which was later sold in Schulten Sale, October 1984, 771; and a second in BM mentioned by Weiser. Our specimen may be the third recorded. Very soon, Procopius introduced his own reverse legend, REPARATIO FEL TEMP, to replace that of Valentinian; soon after that, he reintoduced Julian II's heavier standard for bronze coins and changed the direction of his obverse portrait from right to left. Most of Procopius' surviving bronze coins belong to this large last issue, on Julian II's standard and with portrait facing left." (http://www.forumancientcoins.com/board/index.php?topic=16416.0) Here is another:
A big thanks, Valentinian. You and your site are a valuable resource of information. Topcat7, that has a close resemblance but it is possible I was thinking of that coin. Usually I don't look at those silver issues much. Thanks, Seth, much appreciated. Thanks for all the comments, guys. I am totally convinced that I'm getting it today for a total of $15. Can't beat that deal, considering the rarity of the coin.
The fact that they can easily "fly under the radar" because of their unremarkable look and usual ragged flans and overall rough appearance is maybe one of the key reasons why this issue is still a bit under-represented in collections and dealers tend to overestimate its rarity to get more bucks. I have seen and passed on 2 other offers (at about 100$ they were quite expensive and not much better than your example) but at 15$ it's a bargain despite the condition.
They were even pricier before people on forums started noticing them and all they knew about the type was that a spec. was recorded in British Museum and another published in 1977 and then sold at auction in 1984. Here's for instance one sold in 2001 for 1150EUR: http://www.acsearch.info/search.html?id=49302
That's insane for the price. Probably the price went higher when they realized there was another at the British Museum. lol
Looks like Procopius to me from what I can make of the inscription. A SECVRITAS REIP type exists for Constans as well, a scarce Rome-only issue, typically found in rather rotten grades.
I paid the dealer the money for it and left him a message. I'll hear from him later when he decides to ship it.