Tacitus, AE antoninianus. Siscia. 

IMP CM CL TACITVS P AVG, radiate, draped, cuirassed bust right.
CONCORD MILIT, emperor standing right, clasping the hand of 
Concordia, standing left. 

Mintmark XXIS. 
RIC 183 var (legends and bust type combination). 

With permission of Jean Elsen & ses Fils S.A. - Auction 87, Lot 1584, March 2006.