The mintmarks with lightning bolts are a bit harder to find and this is a nice clear example of the bolt
Constantine I
A.D. 321-4
18mm 3.4gm
CONSTAN-TINVS AVG; Laureate head right.
DN CONSTANTINI MAX AVG surrounding laurel wreath enclosing VOT XX.
in ex. ESIS lightning bolt
RIC VII Siscia 171
