James Mangold’s Star Wars: Dawn of the Jedi movie can finally show audiences the origin of the first lightsaber. Dawn of the Jedi will be a Star Wars movie like no other – instead of focusing on the Skywalker family, the Jedi Order’s heyday, or the rise and fall of the Empire and its offshoots, Dawn of the Jedi will explore a previously uncharted period of the Star Wars timeline. More specifically, it will take place 25,000 years before the Skywalker saga.
https://screenrant.com/star-wars-dawn-jedi-lightsaber-origin-theory/