Chapterhouse

Chapterhouse is the name the Bene Gesserit gave to whichever planet served as their headquarters, so the world it referred to changed over the centuries. The final Chapterhouse was their base from around the death of Leto II onward and was guarded by a ring of no-ships that hid it from prescient searchers such as the Honored Matres. It is the setting of much of Chapterhouse: Dune.