How can I find out the family history of the real Macbeth?
What a great question! I love to research this kind of stuff.
There is a web site called The Real Macbeth. I've placed a link to it in the Sources section. According to this site, the historical Macbeth's name is written in documents as either Maelbeatha, Macbeth, or Makepath. His father was named Findlaech of Moray, and his wife was Gruoch, daughter of Boite and granddaughter of a former King of Scots, Kenneth mac Dubh (Kenneth III, 997-1005). Also according to this site, the Macbeths had no children, but Lady Macbeth had a son from an earlier marriage to Macbeth's cousin Gillecomgain. That son was named Lulach, and he became king at Macbeth's death .
Another web site that tells the story of the real Macbeth reiterates the story that he was the son of Finlaech, Mormaer of Moray, and names his mother as Donada, youngest daughter of Malcolm II. It also notes his wife's names as Gruoch and states that she had a son named Lulach from her first marriage.
I hope this helps. Visit the sites below for more information.