Severus Alexander AR Denarius. 2.87 grams, 18.37 mm. Rome. 222 AD. 

IMP C M AVR SEV ALEXAND AVG, laureate, draped bust right.
P M TR P COS P P, Salus seated left, feeding serpent arising from altar.

RIC 14; RSC 218: Sear 7894.

Used with permission of VAuctions auction 282, Lot 216, May 2012.