City Commemorative AE3. 330-333 AD. Cyzicus. 

Obv: CONSTANTINOPOLI, laureate and helmeted bust of Constantinopolis left, sceptre over shoulder 
Victory standing left, foot on the prow of a ship, holding sceptre 
and leaning on shield,  
Mintmark SMKS.

RIC VII Cyzicus 92, rated R4 (extremely rare)

Victor Clark's collection, 2004
Note: Victor lists this as SMK Epsilon, but I can see an S
at the end of the mintmark.