Severus Alexander. Sestertius. 222-231 AD. 

IMP CAES M AVR SEV ALEXANDER AVG, laureate, draped, cuirassed bust right
SECVRITAS PERPETVA S-C, Securitas seated left by altar, 
holding sceptre and supporting her head on her left hand. 

RIC IV-2, 611; Cohen 537. Common.

With permission of Roma Numismatics, March, 2010