Constantine I, AE3, 318-319, Siscia, Officina 5 - RIC VII, 54 variant (helmet design)
Constantine I, AE3, 318-319, Siscia, Officina 5
IMP CONST_ANTINVS AVG
Laureate, helmeted, cuirassed bust right, * on bowl
VICTORIAE LAETAE PRINC PERP
Two Victories, standing facing each other, inscribing shield containing wreath ties on bottom with VOT | PR above altar with X and pellets design (altar type W)
ESIS in exergue
RIC VII, 54 variant (helmet design)
Note: Although the star in the field of the helmet is the standard for the H11 bust type, field marks on the D6 are rare and RIC does not footnote any examples. This may be a helmet design or a sub-series - more examples are needed to propose a hypothesis and I have only seen three examples with a decorated D6 helmet, all of which are in my collection.
Looking at the helmet design again, it actually appears to be the same as the altar design on the reverse. Something which I did not notice until now and will have to update my website accordingly.