Ancient Roman Coin Question

ColinCMR

What does the big B mean on this coin? Is it a mintmark?

Probus 276-282
AE antoninianus

IMP C M AVR PROBVS AVG

CONSERVAT AVG

S-3347

lordmarcovan

I thought the mintmark on Imperial Roman coinage was usually in the exergue (below Sol's feet on your coin, there). But that looks like numerals, instead. XXX? XXI? I can't see 'em too well in that small picture.

I know of no B mintmark or mintmark beginning with an X, so I am baffled. (Perhaps it is just my inexperience in Roman coins showing.)

ColinCMR

XXI
I think this is an indication of the denomination, an antoninianus.
After the reforms of Diocletian the mintmarks are commonly placed in the exergue, but the exergue consists of only XXI.
I can't find anything about the B though, although I do not have many books on Roman Imperial.

lordmarcovan

I wondered about that. Numerals had to mean a denomination.

So I guess you know as much (or more) than I do on that score. I haven't really gotten that deep into my Sear books, besides a few skimmings.

Something tells me we'll get a visit from The Coach or Automan or Civitas, or even the Dead King who so recently retired from collecting ancients, and they'll set us straight.

canadiancoinguy

XXI refers to the fact that's it's a billon coin with a 1:20 ratio of silver:copper.

What tells you that it's an antoninianus is the fact that Probus is wearing a radiate crown on the obverse. (radiate crown=double denomination. Also used on gold coins)

The B should refer to the coin being struck from the second workshop. Officina marks are usually greek letter alphabets, from alpha, beta, gamma, etc.

ColinCMR

Cool thanks for the help!

I thought it may be the officina marking, but was unsure because of where it is located.