Here's another one in wretched shape. It's impossible to attribute with any surety, but it's probably Constantius II, between AD 337 and 361. The reverse is posted first; if you use your imagination a bit, you can make out the large standing soldier on the right spearing the fallen horseman to the left and below. I knew it to be a CONST- something or other, and some kind fellows on another site used their superior experience to narrow it down more.