Constantine I AE3. 324-325 AD. Trier. 

CONSTAN-TINVS AVG, laureate head right
PROVIDEN-TIAE AVGG, campgate, two turrets, 5 layers, 
star above, no door. 

STR in ex (R resembles an I). 

RIC VII Trier 449. Common.

With permission of Roma Numismatics, August, 2009