The job of historians is to separate the truth of what actually occurred from the myths created by time, misinformation, confusion, and outright falsehood. The unusual problem for magic is the profusion of lies told about magic and magicians. Magicians lie by the very nature of what they do. Magicians lie when they claim to be able to achieve the impossible. Actors, of course, lie too, but not with the consistency or apparent enthusiasm of magicians.
Magicians lie about their origin, their nationality, their education.
Magicians tell you their equipment came from some exotic flea market, from their ancestors, from the attic of a haunted house. Lies, more lies. They talk about fantastic feats they have performed. Still more lies. And when they retire and write their memoirs, they lie there, too.