When and how did the Separatist Movement begin?
I am asking about the separatists before they officially became the Confederacy of Independent Systems. In the second movie, the separatists have gathered on Geonosis before they have announced their intentions to leave the Galactic Republic. The war begins and now the public knows that many systems want to leave the republic. Surprise! For that to happen, they must have been plotting this long before.
An answer to this question says the Separatist Movement began after Darth Maul died, but does not say exactly when or how.
Please answer with quotes from canon sources.