It is asumed that Jedi are created upon Samurai arts and Philosophy, and this is revealed by Lucas and his companies, but in fact the sith are probanly inspired upon ninja, because they s :)tay in clandestinity
Other reference es their competition with Jedi, we know Samurai/Ninja or Jedi/Sith access to the same secrets with variated skills, of course.
More, SW enriches this inspiration with western tradition that relates to mithology, chivalry and Homers of Greece epics.
