Constantine I. AE Follis. 3.46g; 19mm. Siscia. 

IMP CONSTAN-TINVS AVG, cuirassed bust left wearing high-crested 
helmet and holding spear over right shoulder

VICTORIAE LAETAE PRINC PERP, two Victories holding shield 
inscribed VOT PR over altar. 
Altar type Helv. 7x (an X with short crossbar across the centre). 

Mintmark gamma SIS. 

RIC VII Siscia 55. Very rare (R4).

With permission of Roma Numismatics, November, 2009