the frist jedi actually used forced enhanced blades...and were extrodinarly skilled in blade combat...if a jedi/sith from the old republic foguth one of those old masters they would be slaughtered in seconds from the fight, the light saber idea came in much later...(considering the swords are a better idea...much esaier to use if broken and the shards could be used as a secondary weapon if your good enough with the force in combat)
ehh playing the games and paying attention to the detail, plus when im bored i search wikipedia, cant remember exactly which site held that info, but the jedi were originally scholars and other kinds of beings search to be monks in space -_-, however after a couple of centuries and the founding of the new republic, some of these jedi started to argue, and im pretty sure the republic didnt help in that matter (as politics often dont) and the rouge jedi discovered the sith, and after some culture adaptation, they became consumed by their lust for power and greed/envy, as well as desire to rule through power of the republic, but their masters/students/allys really didnt like this after a couple of centuries of arguments (both sides had their greys, lights, and darks) untill the frist force war began due to the fighting getting to much. my take is that it went with a single argument gone to far. and then everyone started drawing blades and cutting each other down.