Marcus Aurelius, AE semis or small medallion, AD 171. 20mm, 6.33 g. 

IMP M ANTONINVS AVG TR P XXV, laureate head right.
COS III, Salus seated left by altar, holding patera and 
sceptre, feeding serpent rising from the altar. 

BMC -. Cohen -. RIC -. NAC 15, lot 376.

With permission of Numismatica Ars Classica.