Constantine I 'the Great' (307/310-337 AD). Rome
AE Follis (19.5mm 2.96g)
Obv: CONSTANTINVS AVG. Helmeted and cuirassed bust right.
Rev: VIRTVS AVGG / P - R / R T. Camp gate, with four turrets and open doors.
RIC 190 var. (unlisted officina).