Aes grave (heavy bronze) is a term in numismatics for the bronze cast coins used in central Italy during the 3rd century BC, whose value was generally indicated by signs: I for the as, S for semis and pellets for unciae.
Standard weights for the as were 272, 327, or 341 grams, depending upon the issuing authority.
Standard weights for the as were 272, 327, or 341 grams, depending upon the issuing authority.

(1)
Rome

Obverse: laureate head of Janus
Reverse: prow of galley left; I
Diameter:
34 mm
Die Orientation: -
Weight: 52.9 g
Die Orientation: -
Weight: 52.9 g
No notes for this coin
Crawford 41/5a; Sydenham 101