Constantine II. Lyons. 321 AD.

CONSTANTINVS IVN NC, laureate, draped, cuirassed bust right, 
seen from the back.
BEATA TRANQVILLITAS (no break!), globe on altar inscribed 
VO - TIS - XX in three lines, three stars above. 
C-R across fields. 
Mintmark PLG

RIC VII Lyons 148, rated R4 

(I now know of 5 examples including this one)

Note: RIC 148 does not have a break in the reverse legend.