Maximianus Herculius, AV aureus, Rome. Struck AD 286–305, 5.30 g. 

MAXIMIA–NVS P F AVG, Bust right, wearing lionskin. 
HERCVLI DEBELLAT, Hercules standing left, wielding club and 
pulling back one head of the hydra whose tail is coiled 
around his leg.
Mintmark PROM. 
Calicó 4661 (this coin); Depeyrot 9/6; Biaggi 1785 (this coin).

Very rare. 
Ex Otto Helbing sale 9 December 1932, 375. Ex Biaggi collection and Arras hoard.

With permission of Numismatica Ars Classica Auction 72, lot 753, May 2013.