I don't know anything about coins that old,
but Looks like a cool old coin.
How about posting the other side too?
This website shows a coin with a similar looking battle scene...
http://augustuscoins.com/ed/numis/intro2.html
Late (4th-5th century) roman coin. The inscription on the back reads FEL TEMP REPARATIO. I'm not sure what the mint mark reads, and if the other side is toasted, unfortunately, that's where the identification of the emperor would be.
I'm guessing that since it is smaller than a penny, in the books it would either be listed as an AE3/4 or an AE4.
-- Tom