Constantius II. AE23 of Aquileia. AD 337-361, 4.38 g. Struck AD 352-355. 

DN CONSTANTIVS PF AVG, pearl-diademed, draped, and cuirassed bust right; A behind head.
GLORIA ROMANORVM, emperor standing half left, holding labarum and 
raising a turreted woman kneeling right.

Mintmark AQT. 
RIC VIII 186 = Mazzini 140 (this coin). 
Extremely rare (R4)
Apparently the only published example.

Ex White Mountain Collection; Ex Aes Rude Sale 5 (April 1980), lot 347.

With permission of cngcoins.com, May 2010.
Estimate: $500