The Gaulus sector, which is also referred to as the Ryloth sector, existed as a sector situated within the Outer Rim Territories area of the galaxy. The Ryloth system was found within it; this system contained the planet called Ryloth, the location where the battle that took place during the Clone Wars occurred.
After the rise of the Galactic Empire, a group of the Twi'lek species, who were originally from Ryloth, started a rebellion against the Empire known as the Ryloth Insurgency. This uprising caused the Sith Lords Darth Sidious and Darth Vader to visit the world.