The Tupile Treaty was a document created by the Guild so that when signed, the location, or locations, of the planet, or planets, called Tupile would remain a secret.
For ten years, from 10195 AG to 10205 AG, the Spacing Guild and the Imperial Council negotiated over this treaty. The Guild wanted it to be signed by Paul so that the secret location(s) of Tupile would remain secret. However, if signed, they would not tell Paul of Tupile's location.
Paul would not sign, but did agree with the Guild not revealing its location, since it was the "sanctuary planet" for Great Houses that were defeated in a War of Assassins.
In 10205 AG, Paul finally agreed to sign, but only if the Guild were to make the Ixian Confederacy submit to his Imperial tax. The guild then stopped all trade of Ix, the Confederacy submitted, and the treaty was signed.
- Dune Messiah (First appearance)