Constantine I AE Follis, London. 316 AD. 

CONSTANTINVS P AG, laureate, cuirassed bust left.
GENIO-POP ROM, Genius standing left, modius on head,
loins draped, holding patera and cornucopiae.
S-P across fields.
Mintmark MSL.

RIC VII London 66 var (bust type)
Very rare

With permission of ArtCoins Roma, Auction 6, Dec. 2012.