Postumus, AE double sestertius, AD 263-265. Mint II. 30 mm, 13.67 g.

IMP C POSTVMVS P F AVG, radiate, draped and cuirassed bust right.
[A]DVENTVS AV[G] (S retrograde), Postumus on horseback, 
riding left, holding spear and raising right hand.

RIC 191; Cohen 3; Bastien 322.

Extremely rare. The two other known examples are in the 
Paris cabinet and are the coins listed by RIC, Cohen and Bastien.

With permission of cgb.fr, sale June 2014, lot 214.