Quadrans

The Quadrans (plural quadrantes) was one-quarter of an As, or half a semis. Originally the quadrans was a relatively large bronze coin weighing around 65 grams, but by the time of the empire it had been reduced to a small coin of around 3 grams. Other than a brief issuance of Uncia under Hadrian, the quadrans was the smallest denomination in the Roman monetary system. It was struck in relatively large quantities from August to Nero but then began to be phased out, with the last quadrans being issued under Hadrian.