What Does The Xxi Represent.

Silver content - traditionally interpreted as 20 (XX) parts copper to one (I) part silver (this means roughly .047 silver content, or very low grade billon).

"H" is not short for Heraclea - they hadn't yet invented the first-letter-of-the-city-name concept of a mintmark when this coin was made. H is the Greek numeral 8, meaning the eighth officina (minting-house within the city). Exactly which city isn't stated on the coin; we need to rely on archaeological evidence to know the city of origin is Antioch.

There is more to this story.

So we know we have XXI as a value mark and whether it is 20:1 ratio or 21 as a value is still debated.

Let me focus in on Tacitus:-

Here is a normal Antioch with XXI:-



They also produced Doublevalue coins with XI rather than XXI



On some issues the value mark was represented in Greek letters i.e. KA

(This coins from Serdica for illustration)



Tripolis produced a double value coin with IA



Regards,
Martin

Got this Diocletian as well, which mint would this be from please?

Thanks, Kevin.