There are various accounts of the true story of the "real" Macbeth. The similarities between Shakespeare's Macbeth and that of King Macbeth of the eleventh century revolve around the fact that Macbeth killed Duncan, Malcolm ascended to the throne after Macbeth's death and Duncan and Macbeth were in fact related.
The differences are where the controversy lies as there are conflicting stories. Macbeth's Duncan is a kind and considerate king, successful in battle, whereas the real Duncan was a "man of many sorrows" and his reign was at first uneventful and later unsuccessful, Macbeth defeating him at Moray.
- A stark difference then would be the way Duncan dies. The real Duncan died in battle therefore indicating a noble battle and an honorable killing.Shakespeare's Duncan was murdered in his chamber by a Macbeth whose "vaulting ambition"(I.vii.26) and over-zealous wife led to murderous actions.
After Duncan's death, in the "real" version, Duncan's wife flees taking her sons Malcolm III and Donald III away.
- So another difference is the mentioning of Duncan's wife who does not feature in Shakespeare's Macbeth. The ages of Malcolm and Donald therefore also differ as they are adults in Macbeth. The place they went is also not certain but they apparently remained together - unlike Macbeth.
There is confusion and thus no real consensus over the death of the real Macbeth who was killed by Malcolm III - the future King of Scotland - but the location of his death and whether he dies immediately or later remain unresolved issues. In Macbeth, it is MacDuff, in battle with Malcolm, who actually fights and kills Macbeth - "Lay on, MacDuff."(V.viii.33)
- Therefore, we see that Shakespeare's Macbeth, a "tyrant ..."will not yield" (27-28) and fights MacDuff to the end. The real Macbeth was killed, as aforesaid, by Malcolm.
Whether Macbeth was a tyrant is also not clear historically and part of the problem is that Macbeth became almost a legend and, like many legends, the factual details may have become clouded as people passed the story on - and perhaps embellished it for their own purposes.
Shakespeare, himself, ensured that his audiences were pleased with his version of Macbeth, in particular, James I to whom his allegiances lay.