Byzantine
Justinian I (527-565 AD). Nicomedia. Dated RY 31= 557/8 AD
AE Follis (31.2mm 17g)
Obv: D N IVSTINIANVS P P AVG. Helmeted and cuirassed facing bust, holding globus cruciger and shield; cross right in field.
Rev: Large M between ANNO and XXXI; cross above, B beneath; NIKO in exergue.
Sear 201.