As one delves into history — such ancient, chaotic time! — the more facts become fluid, the stories contradictory. Across the ocean of time and fallible memory, true heroes metamorphose into archetypes; battles grow more significant than they actually were. Legends and truth are difficult to reconcile.
As the First Official Historian of the Jihad, I must set down this record as best I can, relying upon oral traditions and fragmentary documents preserved for a hundred centuries. Which is more accurate — a carefully documented history such as mine, or an accumulation of myths and folktales?
I, Naam the Elder, must write honestly, even if it invites the wrath of my superiors.
Yes, that's right, everything about the Butlerian Jihad in the original Dune novels is just 'an accumulation of myths and folktales'.
Fortunately "The Battle of Corrin" begin with this:
The gravest error a thinking person can make is to believe that one particular version of history is absolute fact. History is recorded by a series of observers, none of whom is impartial. The facts are distorted by sheer passage of time and—especially in the case of the Butlerian Jihad—thousands of years of humanity’s dark ages, deliberate misrepresentations by religious sects, and the inevitable corruption that comes from an accumulation of careless mistakes. The wise person, then, views history as a set of lessons to be learned, choices and ramifications to be considered and discussed, and mistakes that should never again be made.
—PRINCESS IRULAN, preface to the History of the Butlerian Jihad
I wonder what the author(s) want to say here. Could it mean the entire "Legends of Dune" is just a distorted In-Universe history-book by this Naam the Elder guy? That would explain a lot of contradictions