Roman Republic Æ quadrans(22.9mm, 9.66g). Anonymous(Helmet series), 206-195 B.C., Rome mint. Head of hercules right; behind ••• /Prow right; before, sow; above, ROMA; below, •••. Crawford 118/4; Sydenham 272c
Ex RBW Collection, ex Goodman Collection, CNG 45 lot 1286. Reportedly(via private correspondence) purchased from Ernesto Santamaria in 1988 as a fully-anonymous quadrans, revealed to be a helmet quadrans after careful cleaning by K.A. Howes.
The reverse die of this coin exhibits a helmet of an interesting style. I wrote Richard Schaefer regarding it to ask if he had any similar examples in Republican Die Project after I exhausted my own library. His die research suggests that this anomalous helmet style occurs only on one reverse die and is not exhibited on any other die of any denomination of the "helmet" series