The reverse of this coin has a star on the altar. What is unusual is the position of the star-- it is at the bottom of the altar. Normally the star on the altar is in the center. This series is classified by plain altars and decorated altars. A plain altar would be 209 and altar with star (in center) is 213. I am calling this one a variation of Trier 213.
Constantine I
A.D. 319
17x18mm 3.4gm
IMP CONSTAN-TINVS MAX AVG; laureate helmet and cuirassed bust right.
VICTORIAE LAETAE PRINC PERP; two Victories stg., facing one another, together holding shield inscribed VOT PR on altar.
in ex. STR
RIC VII Trier 213 var.