Sorry if this has already been disscussed. In Episode 1 Ki-Adi-Mundi said the sith have been extinct for a millenium yet in episode 3 Palpatine tells the story about a famous Sith, who according to Palpatine the Jedi knew about. This Darth Plaguies cannot have been 1000 years old. Whats going on or have i missed the point?

You missed Palp saying exactly that. That Plaguies found out how to manipulate, or something to that effect, the mediclorens sp? to prolong life, or to keep people from dying. Basically he could stop people from dying and also prolong life. I know that isn't exactly ver batum but it's something to that effect.

Palpatine doesn't say anything that suggests the Jedi knew about Plagueis. He just asks Anakin if the Jedi have told him Plagueis' story, and he already knows he's going to get a "no" answer.

Palpatine only tells Anakin the story to get him to believe that the Sith have powers that the Jedi don't. There's no real reason to believe that Plagueis ever existed at all.

It could be argued that Ki-Adi Mundi was in complete denial, between his Sith line, and how Dooku was a political idealist not a murderer. His big ole conehead was stuck in the sand :P I agree with the other posters' theories though ...