Unknown Copper Coin, Very Old (Roman?) Byzantium Follis

The scans aren't all that good, I know, but I'll also describe on the off chance that someone can figure out what this is. I got it in a bulk bag of foreign coin recently.




It is about the size of a quarter.

On the tails side, there is a large letter M, and just above it, within the "triangle" above the middle of this letter is what appears to be a smaller T. On either side of the M is a dot, and below the M a line from side to side, comparable to the "ground line" on the face of a Buffalo nickel, like so:




On the heads side is the bust of a man, facing right. He seems to be wearing a toga, has longish hair kind of like a Dutch Boy cut with some kind of a band going across it from the top to about the base of the hair. Above him on the left from about 9 o'clock to 11 o'clock is lettering I can't make out, but what appears to be M or A S ? ? ?, but I could be wrong, it's that indistinct.

Any ideas, anyone?