Constantine II, AE follis. Cyzicus. AD 325-326. 

CONSTANTINVS IVN NOB C, laureate, draped and cuirassed bust left.
PROVIDEN-TIAE CAESS, campgate, seven layers, two turrets,
star abvove, no doors. 
Mintmark SMKS dot.
RIC VII Cyzicus 37.

With permission of Emporium Hamburg, Auction 72, Lot 870.
Nov 2014.