Roman Currency in the 4th Century CE ↔ D&D Currency Conversion Tables
I put together these tables as a reference guide for currency units in the setting of my homebrew D&D campaign. I want historical flavor, so D&D denominations just won’t do. With this approach, I tried to balance between accuracy and convenience. By establishing conversion rates to/from Roman currency to D&D currency, I don’t have to come up with my own list of prices for goods and services. However, I will adjust book prices with percentage modifiers to account for inflation when appropriate.
This covers the period from the currency reforms of Constantine to the currency reforms of Anastasius (so, roughly 330 to 500 CE). However, Roman currency during the Empire was basically in a constant (if gradual) state of flux. Older denominations continued to circulate for decades even after major currency reforms. Debasements (and occasional rebasements) would alter the purchasing power of a given denomination and encourage the hoarding of higher purity coins. Some emperors would introduce new denominations, only for them to be abandoned by their successors.
Hence, this chart is based on a considerable amount of simplification, averaging, and speculation: