The Bene Gesserit Chapter House on Wallach IX, the last surviving facility of what was once a network of twelve chapter houses across the Imperium. Located on Wallach IX, it served as the centre for theological and philosophical training, housing the principal Missionaria Protectiva school and the main reference library. Beneath the main building lay three levels of subterranean vaults containing the Bene Gesserit Archives, the most complete and secret records of the Sisterhood's history.