Constantius II AE3. 353-355 AD. 

Obv: DN CONSTANTIVS P F AVG, laurel and rosette diademed, 
draped & cuirassed bust right
Rev: FEL TEMP RE-PARATIO, soldier standing left, right knee 
raised, spearing a fallen horseman who is wearing a Phrygian
 helmet and reaching backwards, S in left field.
Mintmark: RP.

RIC VIII Rome 267, rated Rare.

Offered on ebay, Dec. 2015.