The Elder Scrolls IV: Knights of the Nine is the first official expansion for the fourth installment in The Elder Scrolls series, Oblivion. Announced on October 17, 2006 for release on November 21, 2006, the expansion was developed, published, and released in North America by Bethesda Softworks. In Europe, the game was co-published with Ubisoft. The expansion, along with Shivering Isles, was later included in the Game of the Year edition, as well as the 5th Anniversary Edition of Oblivion.