This Nicaean coinage is really odd. Most 3rd early-mid century
provincial coins
types did not circulate widely beyond their proper city. These Nicaea coins are an exception and are common finds in the Balkans hundreds of miles from where they were struck. There was clearly something going on with a minting much larger than required by Nicaea itself. So I am guessing they might have
had to scrounge metal from where they could and sometimes used brass from melted down 2nd century
sestertii.
Shawn