Castell was the homeworld of the Gossam; it was located along the Perlemian Trade Route.
The world was discovered by the Galactic Republic between 30,000 BBY and 25,000 BBY, and had joined it before 22,000 BBY. Gripped by economic depression for decades, the Commerce Guild swept in and funneled money into the economy by buying much of the world. This forced the Gossam to work for the Guild if they wanted to keep their property. Shu Mai eventually purchased the planet, yet kept the taxes high. During the Clone Wars, the Galactic Republic recaptured Castell from the Confederacy of Independent Systems, prior to the Outer Rim Sieges. To Presidente Mai's dismay, Count Dooku indicated this was merely part of his plan.