Rare follis of Helena, in the Roman Imperial Coinage catalog, rarity R3.
Roman Imperial
Helena Augusta (325-329, mother of Constantine), Follis 325-326, Nicomedia mint
Obverse: diademed and draped bust right
FL HELENA AVGVSTA
Reverse: Securitas standing left, lowering branch with left hand, raising robe with right hand, MNΓ in exerque
SECVRITAS REIPVBLICE
Diameter 18 mm, weight 3.01 g