Planet of Ix
The Planet of Ix is a fictional planet featured in the Dune novels by Frank Herbert.
Its name is derived from the Roman numeral IX because it is the ninth planet of its solar system, although this is largely forgotten, and it specializes in the production of complex machinery including the Guild Heighliners and fighting machines. Often these machines flaunt the proscriptions of the Butlerian Jihad which forbids the making of a machine in the likeness of the human mind.
The planet is a fief ruled by House Vernius, except for the main part of the Prelude to Dune where House Vernius had been overthrown by the Tleilaxu, who were acting in conjunction with the then emperor Elrood IX. Elrood, who desired a Melange substitute and who wanted to pay back Dominic Vernius for two offenses against him (stealing a concubine - later to be called Shando Vernius from Elrood and making larger Heighliner ships, stripping Elrood of tax revenue), decided that a Tleilaxu invasion of Ix would kill two birds with one stone.
The Tleilaxu invade in Dune: House Atreides, on the (somewhat justified) pretext that House Vernius were creating thinking machines (a fighting Mek was created shortly before in the story) and are driven out of Ix in Dune: House Corrino.