Roman coin [решено]

Hello,
I need help again.
Mint: XXI
In Field: crescent over H
Weight: 4.2g
Diameter: 22mm

Thanks for help
Peter

Hello,

It looks like a double struck Antoninianus if either Maximianus or Galerius. I don't know about the reverse, but it looks like IOVI CONSERVATOR...

I think this is a coin of Diocletian from the Antioch mint, struck 290-294 AD.
Reference: RIC vii, p256 #323; Sear #12654.

Obverse (underlined letters can be read from the coin):
IMP C C VAL DIOCLETIANVS P F AVG

Reverse (underlined letters can be read from the coin):
IOV ET HERCV CONSERV AVGG

Mintmark:
͜
H_
XXI

See: https://www.acsearch.info/search.html?id=1334842

Hello,
I almost agree with the comment of numisquare  :
Crescent over the H for the 8th officina of Antioch, "IOV ET HERCV CONSER AVGG" reverse type wih Jupiter facing Hercules, however we differ about the emperor.

I don't think there is a double "C" at the begining of the legend : it's the same one from the two different strikes.
I read "IMP C / C M AVR VAL M[AXI]MIANV[S] P F AVG"
This legend stands for Maximianus.

So RIC V-2 #622 (P294)

Like this one, but with another officina : https://www.deamoneta.com/auctions/view/198/460
Edit : already on numista https://fr.numista.com/catalogue/pieces92852.html

Thanks a lot for your kind help again

Cycnos is correct – the coin is from Maximian, Antioch mint, struck 290-294 AD.
Reference: RIC v part 2, p294 #622; Sear #13134.

Obverse (underlined letters can be read from the coin):
IMP C M AVR VAL MAXIMIANVS P F AVG

For a similar coin see: http://www.wildwinds.com/coins/ric/maximianus/RIC_0622.1.jpg