Constantine I AE follis, London, 317 AD, 

CONSTANTINVS P AVG, laureate and cuirassed bust right
SOL INVIC-TO COMITI, Sol standing left, holding globe and raising hand.

S over star in left field, P in right field.
Mintmark PL-two dots-N. 
Toone 156 var (mintmark with two dots); RIC VII London 123 var (field mark and mintmark).

Extremely rare. Extremely fine.

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