In Act 1, Scene 5, after the ghost of Hamlet’s father reveals the true cause of his death, he begins to advise Hamlet on how to go about seeking revenge. Some of his concerns are eerily similar to Hamlet’s eventual fate, and their presence this early on in the play seems to cement the severity of the subject matter. The King’s death connects violence to the heart of the play’s events from the first scene onward, but these mentions of madness and revenge, fate, and betrayal have the effect of foreshadowing the play’s conclusion and darkening the audience's expectations. The ghost insists that revenge is necessary, but warns:
howsoever thou pursues this act,
Taint not thy mind, nor let thy soul contrive
Against thy mother aught
This warning serves to foreshadow Hamlet’s eventual descent into insanity. The Ghost seems to foresee this potential conclusion, and his mention of it makes it imminently present and possible in the minds of the audience as well. Then, when Hamlet doesn’t manage to avoid turning against his mother or falling into madness, the audience is forced to conclude that they were forewarned of these horrible events. This has the effect of making Hamlet’s fate seem inevitable. Even with this heeding, he cannot wrest himself from the road he was meant to travel down. Because his fate is as confusing and gruesome as the ghost seemed to anticipate, there is an added impression of meaninglessness to the violence and to Hamlet’s eventual supposed insanity. The audience is left to understand that the ghost’s warning was, in fact, a signifier of what was to come.
In Act 3, Scene 2, most of the characters gather before the players put on their performance for the King and assembled crowd. It is a significant scene, a major contributor to the rising sense of tension, and as the characters mill about beforehand, their interactions give an indication of what is to come. Though the conversations appear casual, each character’s motivations drive them to engage with each other and ultimately have important repercussions. Hamlet and Polonius greet each other first, and Hamlet is purposefully inscrutable, confusing Polonius and Ophelia. Hamlet asks Polonius to confirm that he was an actor in his youth, and then he continues his line of questioning:
Hamlet: What did you enact?
Polonius: I did enact Julius Caesar. I was killed i’ th’ Capitol. Brutus killed me.
This is a moment of significant foreshadowing, as both men allude to the betrayal of the Roman general Julius Caesar by his fellow politician, Marcus Junius Brutus. This reference to Polonius’s role as Julius Caesar foreshadows his violent death by stabbing. That Caesar was killed by Brutus—finding his demise at the hand of a friend—further complicates the reference, since Hamlet ends up being the one to murder Polonius. There's a parallel, then, between the two deaths, both of which are bloody and enacted in the same way.
