Constantine I AE3. 

Obv: CONSTANTI-NVS MAX AVG, rosette-diademed, draped, cuirassed bust right 
Rev: GLOR-IA EXERC-ITVS, two soldiers holding spears and shields with two 
  standards with triangular banners between them. 
Mintmark: dot in crescent PLG. 

RIC VII Lyons 253, rated R3

Contributed by Dane for George Clegg (biggyg2), October 2007