Usurping a divinely appointed ruler was always the most serious of crimes, but to usurp a valiant and benevolent monarch was wicked beyond comprehension. Thus, for reasons both dramatic and political, Shakespeare had to make notable changes to the historical Duncan. The real King Duncan, according to Shakespeare's sources, was your regular nasty warlord; nastier, it appears, than the actual historical Macbeth. If Shakespeare's Macbeth planned to kill this Duncan he would be justified, and hence there would be no play. So Duncan morphs into a delightful and much beloved ruler, kind to the point of annoyance. With his 'silver skin' and 'golden blood' (2.3.97), Shakespeare's Duncan epitomizes the perfect ruler. Shakespeares changes to Duncans character are also in keeping with other changes he made to his sources, all seemingly intended to cater to his king and patron, James I.

