Knowing that Yoda would need to preserve his consciousness after death, the spirit of Qui-Gon Jinn guided his old friend to a group of Force Priestesses who challenged him to see if he was worthy.

Source: https://screenrant.com/star-wars-essential-yoda-stories/

Qui-Gon Jinn, although idolized by viewers, may not have been right in everything he did and could have been the reason for the fall of the Jedi Order.

Source: https://screenrant.com/star-wars-qui-gon-jinn-reason-jedi-fell-theory-explained/

Star Wars: Episode I - The Phantom Menace, Jedi Master Qui-Gon Jinn was murdered by Darth Maul, a new Sith Lord who himself was defeated by Obi-Wan Kenobi.

Source: https://screenrant.com/star-wars-george-lucas-sith-rule-of-two-misunderstood/