Mars, helmeted, standing right (?), holding spear and shield.
Reverse script
Latin
Reverse lettering
PONTIF
TR P XII COS III S C (Translation: Pontifex [Maximus], Tribunicia Potestate Duoecima, Consul Tertium. Senatus Consultum. [High] priest, holder of tribunician power for the twelfth time, consul for the third time. Decree of the senate.)