Correct me if I'm wrong, but I believe most of what we know of William Wallace comes from a ballad by a minstrel called Blind Harry that was written after the fact.

Of course, in the U.S. we have Frank and Jesse James, who owe much of their repututations to minstrelsy.

"Macbeth" was my father's favorite play. I don't remember a time in my life when I didn't know it, and I can recite hefty chunks. But it doesn't have a lot to do with what actually happened.

As an interesting addition: At New Orleans, General Packenham built a barricade of barrels full of sugar. Anybody who knows what happens when sugar burns would have told him that was a recipe for disaster.
If Packenham had learned to cook at some point in his life, history might be different.