Perhaps this page will facilitate communications by leveling the playing field. Unfortunately, pigeonholing history is not all that simple. By that year, the center of the Roman world had been moved East to Constantinople and would continue more or less uninterrupted until 1453 AD when the Byzantine empire fell to the Ottoman, Muhammad the Conqueror. Many collectors choose not to separate the Eastern Roman and Byzantine periods and collect both even thought they do not collect medieval coins from western Europe or the rest of the world. Perhaps it is better to understand that history does not come in the neat little packages some would prefer.
Coins are pieces of metal of pre-determined value used to facilitate commerce and represent wealth.
Before coins existed, lumps of metal were weighed and used as items of value. Standardized lumps made it unnecessary to weigh the metal before each transaction. The next step was to mark the lumps with a sign that they were appropriate for commerce at the standard value. Stamped ingots of various weights and standard sized but unmarked lumps are included or excluded by persons of differing opinions. If you were seeking a precise date and place for the invention of coinage you won't find it here.