Need help identifying this coin

oilers99

Thanks for any help with figuring out what this coin is.

Sapyx

Ancient Roman, of the type known as "Late Roman Bronzes". More specifically, it appears to be Constantine the Great (CONSTANTINVS MAX AVG), reverse type GLORIA EXERCITVS (Glory to the Army). The mintmark is below the exergue-line on the reverse, but can't read it in this picture.

tcollects

how do you know how to identify coins from 500 BC to the present so well, Sapyx? a true numismatist!