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Nero & Statilina Messalina, AE as, Galba ctmk.

Nero, Æ27, (10.54g) Nicaea, Bythinia, 
NERWN K[LAY]DIOS KAISAP SEBASTOS GE, Laureate head left, rectangular countermark GALB[A].
ME[SSALEIN]A [GYNE SEBASTOY] Statilia Messalina as Securitas 
seated right. 

cf. RPC2061(3 known right facing, same reverse die as RPC plate coin), countermark Howgego 591.