The Old Republic era in Star Wars predates the Skywalker Saga by thousands of years and features the Jedi and the Sith at the height of their power in countless grand battles. The era was first explored in the beloved Star Wars: Knights of the Old Republic video game launched in 2003. Since then, many stories set in the era have been told in gaming, comics, novels and flashy cinematics.
Source：https://www.cbr.com/lucasfilm-old-republic-not-in-star-wars-canon/
