Forum:KB:Rule of Two

At the end of The Phantom Menace, Yoda and Mace Windu express knowledge of the Sith Rule of Two. But I understood that the Rule of Two was only created about a thousand years earlier by Darth Bane, and that Bane's Order had been in hiding from the galaxy since that time. So if this was the Jedi's first encounter with the Sith since then, how could they be aware of the Rule of Two?