Maybe these are embellished stories based on information found in a time capsule from a now dead galaxy.
Scientists took devices from the capsule and reverse-engineered a lightsaber (the experiments are rough; the saber blade stays on for a few seconds, flickers out). "Jedi Knights" are the hypothetical warriors who would have wielded these. Translators worked tirelessly on a holographic card with scattered reports of war with an Empire and a devastating weapon. We have names of people, planets, species, technology, but it's difficult to piece it all together into something coherent. For all we know, Luke, Leia and Han lived in different time periods and never actually met.