I just got this one...it is ex- Failmezger, in his book Roman Bronze Coins: From Paganism to Christianity 294-364 A.D.
Helena
A.D. 318- 319
18mm 3.1g
HELENA N F; draped bust right.
REV: eight rayed ✶ in laurel wreath.
in ex. TSA
RIC VII Thessalonica 48
