Macbeth, line of succession?

Question:In Shakespeare's Macbeth, why is it that Macbeth becomes king after Duncan is killed, and not anyone else?

Best Answer - Chosen by Asker: In Shakespeare's Macbeth, why is it that Macbeth becomes king after Duncan is killed, and not anyone else?

Because the Kingship wasn't decided by heredity at this point in Scottish history, but was bestowed on someone who had behaved honorably in battle. Also, at the time that Macbeth is given the throne, Duncan's sons are under suspicion of having paid the guards to murder their father. The sons both flee (one to England, one to Ireland) so they are not about to be made king. Macbeth already distinguished himself in battle before the play began, and was a high ranking thane of Glamis and Cawdor, so he actually had reason to believe that he would've been named heir (Prince of Cumberland) and is surprised when Duncan bestows that title on Malcolm.

Hope this helps!