 Some players, actors, have come by, as they did in that period. They wanted to perform at the palace of the king of Denmark, and so Hamlet says, good, that's what I need. And he invites them in, and he asks them if they know a certain play, and they do, and then he makes a few changes in it, so that the details of the play are the same details of the murder that had been told to him by the ghost of his father.