A relatively young great house, House Vernius was only a few centuries old by the time the Leto Atreides I became Duke of their Faufreluches ally, House Atreides. A fire red ruby ring from Hagal was the sign of their Earl.
House Vernius specialized in technological innovations. After an intense economic war with House Richese they won the right to manufacture the lucrative Heighliners for the Spacing Guild.
Reign under Earl Dominic Vernius
While still a young man, Dominic Vernius lent Ixian forces to the Padishah Emperor Elrood IX to assist against the Ecazi Revolt and restore the Archduke Ferdinand Ecaz to the Mahagony Throne. It is during this time that he met and befriended Duke Paulus Atreides of Caladan. As a reward for his loyal service, the Emperor had expanded House Vernius' fief to include several more planets.
Fall from Grace
After the war, Dominic stole Lady Shando from the Emperor and earned his undying enmity. They had two children, Rhombur and Kailea Vernius. Years later Tleilaxu forces seized Ix with the help of the Suboid working class with assistance from the Emperor. Ixian ambassador Camaar Pilru attempted to garner Landsraad support in retaking his planet but the Tleilaxu accused the Ixians of creating thinking machines and therefore justifying their acts. House Vernius was forced to go renegade while Sardauker forces landed on Ix to "keep the peace". The Vernius children were secretly sent to Caladan under the protection and care of Paulus Atreides. Lady Shando was executed by Sardaukar forces while Dominic hid on Arrakis with some loyal men. Eventually he was caught and he detonated a stone burner, ending his life.
Return to Ix
After almost 25 years Gurney Halleck and Prince Rhombur Vernius returned to Ix to conjure a rebellion to help the soon to arrive Atreides forces to liberate the planet. After a brief but bloody battle with the Sardaukar, the allied forces were victorious, and Prince Rhombur went to the Landsraad to formally restore House Vernius. He ascended and became Earl Rhombur Vernius of Ix.
Behind the Scenes
Continuity issues
The Frank Herbert novels make no mention of a Great House ruling Ix. Indeed, the ruling body of Ix is only referred to once in Dune Messiah, where it is mentioned that Ix is ruled by a confederacy. Moreover, heavy mention was made in the Brian Herbert and Kevin J. Anderson prequels that House Vernius was a strong ally of House Atreides. However, in the original Dune book, there was no mention of a House Vernius (or the Ixians for that matter) coming to Duke Leto's aid when his House was attacked by the Harkonnens and Corrinos.
Within all of the Frank Herbert novels, the inhabitants and rulers of Ix are only ever referred to as "Ixians" and not members/subjects of House Vernius. In the Frank Herbert novel God Emperor of Dune, a Bene Gesserit analysis of various power brokers in the known universe have Ix listed as a separate entity from Great Houses of the Landsraad.
Finally, one of the key plot points of the original Dune novel was that, the combined Harkonnen/Corrino attack on House Atreides and Arrakis required that Corrino complicity in the attack had to be secret. This was because it defied the Great Convention. Had the complicity been exposed, all the Great Houses would have united against House Corrino, because the attack was illegal, because Leto Atreides was liked in the Landsraad, and because the Great Houses feared being attacked one-by-one by the Sardaukar (a point Paul Atreides makes when discussing the attack with Liet-Kynes). This is why the Sardaukar invasion force on Arrakis had to wear Harkonnen uniforms. The Sardaukar's open attack on House Vernius and Ix, and its subsequent occupation, completely ignores these issues.
Edit Note: The Sardaukar do not openly attack Ix. The Tlelaxu subvert the Ixian suboid population, making them revolt against the leaders of Ix. The Ixian ambassador pleads for assistance from the Emperor, but because it is all part of Shaddam Corrino's plan, he is ignored. The Tlelaxu subjugate Ix, and Padisha Emperor Shaddam Corrino sends Sardaukar to Ix to help the Tlelaxu subdue the rebel factions that appear after the takeover. Because Ix's internal affairs are completely closed off to the rest of the empire, there is no open knowledge of the Sardaukar presence. In fact, it is noted by some characters that the Empire's strength seemed to wane, and that they were promoting more officers than they were getting recruits. This is because the soldiers stationed on Ix were off the books. It is similar in many respects to the tactics used against the Atreides, which should be expected as they were both perpetrated by the same man.