Thirty years before the play opens, Fortinbras' father was killed by King Hamlet (Prince Hamlet's father) in single combat, thus forfeiting land to Denmark. Now, as the play opens, after the death of King Hamlet, Fortinbras has been preparing to fight Denmark. When Claudius gets the King of Norway to control his nephew Fortinbras, he then gives Fortinbras permission to cross Danish soil (2.2) in order to attack Poland for a worthless piece of land (4.4). Fortinbras is portrayed as a man of action whom Hamlet nominates to succeed Claudius as king of Denmark.

Fortinbras (Rufus Sewell) in Branagh's 1996 film. Rolf Konow & Peter Mountain