Constantine I AE3.

Obv: CONSTAN-TINVS AVG, laureate head right 
Rev: VIRTV-S AVGG, campgate, 4 turrets, 6 layers, star 
above, open doors.
S-F across fields.
Mintmark: PCONST. 

RIC VII Arles 321 var (headwear).

Contributed by Robert Edwards, Feb. 2015.