Diocletian, Post abdication Follis, Serdica, AD 305-306. 

DN DIOCLETIANO FELICISSIMO SEN AVG, laureate bust right, wearing 
imperial mantle, holding olive-branch and mappa.
PROVIDENTIA DEORVM QVIES AVGG, Providentia standing right, 
extending right hand to Quies, standing left, holding branch and sceptre. 

S-F across outer fields. B in lower centre.
Mintmark SM dot SD dot. 

RIC VI Serdica 15a; Sear 12940.
Rated common.

With permission of Numismatik Naumann Auction 40, Lot 667, Feb. 2016