Maybe this is an odd question, but I'm an odd newcomer to Roman coins. I have seen mention of coins depicting one ruler (or other dignitary) under the authority of another ruler, especially in the case of posthumous issues or other relatives like the Helena I have. How can I identify such coins and who issued them if it isn't the man on the obverse? Thanks again!
There's no exact formula. Posthumous issues are often signalled by the word "Divus" or variant, meaning the person was consecrated as a god at or well-after death, which is also signaled by variations on "consecratio". "Div" sometimes confusingly refers to the parentage of that person, however. But it's a good clue. In the early Empire, there are a few exceptions that are not obvious. Claudius put his deceased mother and father (see my avatar) on coins without his own name or consecratio. Caligula put his dead parents, brothers, and (probably) grandfather Agrippa. Nero put his living mother (or, more likely, she put herself) on some coins. But usually, there's a reference to the actual issuer somewhere on the coin with the imperial titles, such as C CAESAR AVG GERMANICVS PON M TR POT, or with filiation signalled by "MAT[er]" or P[ater], but not always. All Imperial coins were issued by the current ruler (or rival) so there are no private issues to worry about. Provincial coins are a hodge-podge. They sometimes depicted a living relative of the Emperor, often as a patron of the city. So, the best way to be really sure is to find a good book or website!
Sort of similar to OP's question: is there any way to tell WHICH of Constantine's sons issued any given posthumous (DV CONSTANTINVS) coin?
In the general sense that the 3 sons controlled different parts of the empire, so the coins from the mints within their respective parts could be said to have been issued by them
OCRE lists this info for each coin @hotwheelsearl based on what @Kiaora said I think. Not sure how accurate it is, I saw one the other day attributed to Licinius that I think should have been attributed to Constantine's own authority.
