Decentius. AE. Trier. 350-353 AD. 

DM DECENTI-VS FORT CAES, bare-headed, draped, cuirassed bust right
VICT DD NN AVG ET CAES, two Victories facing one another,
 holding between them a wreath inscribed VOT-V-MVLT-X, letter
 I in lower centre. 

Mintmark TRP. 

RIC VIII Trier 317 var (field mark). 

Unlisted with the short reverse legend and the letter I in the centre. Possibly unpublished. 
The normal RIC 317 with no fieldmark is rated R2. 
The letter I is not a column, as Decentius' coins of the 
type with no letter behind the bust and with the short 
reverse legend do not have a column.

With permission of Roma Numismatics, Oktober, 2009