[Romulus]

Diocletian’s reign was a time of runaway inflation, which he sought to control through price controls. It didn’t work. It is easy to see why he would have been hostile to an artificial expansion of the money supply. For the record, it was the Christian favoring Constantine who stabilized the economy through introduction of the gold solidus.

[Antoninus]

It is easy to see why he would have been hostile to an artificial expansion of the money supply.

Agree. He apparently took away Alexandria's traditional right to coin money after the rebellion as well. One wonders if the Alexandrians were using "alchemy" to make base-metal coins appear to be gold or silver -- that is, counterfeiting.