This comment on a recent /r/AskHistorians thread piqued my interest on the importance of coins during Roman times. As the comment says, coinage was frequently used as a means of transferring news and propaganda. With the Roman Empire eventually growing to be incredibly expansive, how were new coins introduced (to large, urban regions as well as far off territories) that kept up with current events and new emperors? Also, how were old coins handled?
*edit for clarification and spelling
One of the primary ways the coins got circulated was through the local legions and town guards, and in the later empire, through the imperial bureaucracy. Newly minted coins would be used to pay soldiers, and if the soldiers weren't fighting they'd be stationed in or near major cities where they would then spend their newly minted coins. From their the coins would be further distributed by merchants and traders. With legions stationed on frontiers all over the empire, it didn't take all that long for them to be circulated.