Maximianus. (286-305 AD). Gold aureus (5.28 gm). Rome. 

MAXIMIANVS P F AVG, laureate head right.
HERCVLI DEBELLAT, Hercules standing left, holding one of Hydra’s heads with his left hand, and with his right hand raising his club to strike the creature, which is wrapped around his right leg. 

Mintmark PR. 

Calico 4659a (this coin). Depeyrot 6/13; Cohen 255. 
Apparently only the second specimen recorded.
Ex Leu 65, 21-22 May 1996, lot 480. 

Sold for US$ 22,000.
Re-used by permission of Harlan J Berk and Freeman & Sear.
Gemini III, January 9th, 2007, Lot 450.