In Chris Taylor’s book “How Star Wars conquered the universe” he says this about Lucas’ very earliest attempt to formalise the story in 1973:
Lucas saw an ancient order of galactic guardians called Whills. We wouldn’t get to see them; they would be chroniclers in the background. The whole movie would be drawn from a book we never see, a book he could keep fleshing out for years if this little space thing worked. “Journal Of The Whills,” he wrote “Part 1. This is the story of Mace Windy, a revered Jedi-bendu of Ophuchi…”