Spacing Guild
In the fifth and sixth novels of the series, "Heretics of Dune" (1984) and "" (1985), 5,000 years after the reign of Paul Atreides (a period that includes 3,500 years of Leto II's reign and 1,500 years following his death), the Honored Matres have seized control of Junction, the old Spacing Guild complex above Gammu. The technocrats of Ix develop technology that the Ixians and the Administrative faction of the Spacing Guild refer to as "compilers". These compilers perform calculations very similar to computers, nearly violating the prohibitions against "thinking machines" that were imposed following the Butlerian Jihad several millennia before. These compilers eliminate the need for the Navigators, and the strategic disadvantage that this aspect of melange dependency has become, because the Navigators' abilities are slowly being compromised by the severe reductions in the availability of spice resulting from the destruction of Dune and the sandworms on that planet, and the strict control by the Bene Gesserit, who maintain a monopoly over the largest stockpiles of melange. The prescient rule of Leto II that lasted 3,500 years has shown the universe the perils of prescience, namely that the entire universe can be locked into the vision of a single entity, giving that entity absolute power. The Guild, facing obsolescence and suspicion, couples itself with Ix in decline; Navigators continue to exist, but their importance in the universe is severely diminished.