MAXENTIUS. AV Medallion 4 aurei (20.90 gr). Carthage. 307 AD. 

IMP C M VAL MAXENTIVS P F AVG, Bare head right.
MARTI CONSER-V AVGG ET CAES N, Mars standing right, holding shield in left hand and transverse spear in right.
Mintmark PK. 

RIC -. C -. Gnecchi -. 

Ex Spink sale 114, 1996, 109. 

The portraiture of Maxentius, generally minimalist in appearance, seems in keeping with his grassroots appeal to the patriotic instincts of his fellow Romans. It perhaps is no coincidence that his portrait, though in line with the conventions of his age, has an almost indescribably anachronistic quality, as if it was unearthed from the ashes of the Republic itself. On medallions such as this, where Maxentius does not don the laurel wreath, the antique quality of his image is only magnified. The reverse of this four-aureus medallion pays homage to Mars, the god of war, and describes him as preserver of the two emperors and the one Caesar. We must presume that the two emperors are Maxentius and his father Maximian, and the Caesar is none other than Constantine the Great, for whom he also struck medallions. 

Photo and description courtesy Numismatica Ars Classica, April 2010.