And they brought it
 The penny, which was a Roman one, and worth seven pence halfpenny of our money: 
 and he saith unto them, whose is this image, and superscription;
 for it had the head of an emperor upon it, very likely the image of the then reigning emperor Tiberius, and a superscription on it, expressing his name, and perhaps a motto along with it: 
 and they said unto him, Caesar's;
 one of the Roman emperors, Augustus, or Tiberius; most probably the latter; (See Gill on Matthew 22:20), (See Gill on Matthew 22:21).