Help identify this Roman coin please!

[Trinitial]

I have a Roman coin that I need help with.

The reverse side has an image that looks like a man stabbing another with a spear. On the bottom left, it has letters "SISA" (well that's what it looks like) from left to right.

The obverse, like always, has a head. The man has kind of a long face.

I don't have any pictures, sorry!

 

[prospectordamon]

be more specific, there are hundreds of roman coins, is the man doing the spearing on a horse and the man being speared laying on the ground?

 

[lazooro]

fallen horseman... Constantine era cca. 330-350AD?
Siscia- Sisak Croatia.