Tacitus AE Antoninianus, Cyzicus. 

IMP CM CL TACITVS AVG, radiate, cuirassed bust right
SPES PVBLICA, Victory on left, facing right, holding palm and 
presenting wreath to emperor, standing left, holding sceptre. 

Officina letter S in ex. RIC V (1) 208 var (officina letter).

In view of the fact that RIC 167 does not list this bust
type but RIC 208 does have the mintmark P, V etc, the
mintmark S (Secundus) would be expected after P (Primus).

AAH sale 2003