This example has wear on the front, but less on the back. The planchet resembles ones from Lugdunum or Izmit, because of the thin, round, compressed appearance. I'm guessing the coin is an AE2/3 or maybe a Follis. The obverse looks to be a helmeted soldier, possibly Minerva? With two readable letters on the left. The reverse looks to be a griffin, hound, or something else standing front with an inscription on the bottom that reads "*JKT" or maybe "*JKC". Tell me what you guys think.
The coin is an VRBS ROMA commemorative featuring the personification of Roma on the obverse and the she-wolf suckling Romulus and Remus on the reverse. Struck under Constantine (late in his reign, 332-337 A.D.).
@ancient coin hunter has correctly ID'd the type. The mintmark on reverse looks to me like "(something)MK(gamma)", which could be SMK(gamma) and thus Cyzicus, third officina. Someone who specializes in this area can probably come along soon and give full citations (or else tell me why I'm completely wrong).
I have several of these VRBS ROMA coins. Here's one from the same mint but a different officina: Constantine I, AD 307-337. Roman billon reduced centenionalis, 2.09 g, 17.4 mm, 1 h. Cyzicus, AD 331, 333-334. Obv: VRBS ROMA, bust of Roma, left, wearing plumed helmet and imperial cloak. Rev: Lupa Romana standing left, suckling the twins Romulus and Remus; two stars above; SMKS in exergue. Refs: RIC vii, p. 656, 91; LRBC I 1232; Cohen 17; RCV 16523.
