Constantine I AE3 with VOT shield

From Curtis Clay: Fascinating discovery! I find no such coin with legend on shield in Bastien's Lyon 294-316, nor in the two supplements to that work. No such obv. type of Constantine I was known to Cohen at any mint, though we cannot exclude the possibility that such a coin may lie in some known collection, with inscription like yours that no one has yet noticed!

From Barry Murphy: Interesting coin. It's not recorded in Bastien with the inscribed shield either. I'd be cautious though. It's possible the shield has been reengraved and then had the desert patina added to hide tooling marks. I wouldn't accept it as a true variety until the dirt is removed from around the lettering.

From Curtis Clay: I think Barry's proviso may be overcautious, because of the source as you say, and because the inscription and patination look convincing in the image to me, and obviously to you too in the flesh! I think autopsy should suffice to establish authenticity. Removing the patina should not be necessary, though you could consider that option anyway to improve the coin's attractiveness. If it's a forgery, it's an educated one, since the legend VOT X SIC XX is specifically appropriate to this issue, (1) because the issue is dated to Constantine's decennalian year 315 by the title COS IIII on a few rare Lugdunese coins, and (2) because a unique piece in the preceding issue has rev. VICTORIA AVGG NN, Victory inscribing VOT X on shield set on palm tree (Bastien 558, pl. LXII)!