Antoninus Pius Mule: rev. of Marcus Caesar. Denarius

Antoninus Pius Mule: rev. of Marcus Caesar; 138-161 AD, Rome, 157 AD, Denarius, 3.24g. Cf. Strack-318. Obv: ANTONINVS AVG - PIVS P P IMP II Head laureate r. Rx: TR POT - XI - COS II Felicitas standing l. holding short caduceus and scepter. Ex Curtis L. Clay Collection. A rare mint error, combining a reverse die of Marcus Caesar with an obverse die of Antoninus Pius as IMP II (156-159 AD).. EF