The separation of the brain from the body to become a cymek is like that invented by the cogitors, philosophers who had their brains removed from their biological bodies and installed into towers and tanks in order to live longer, simpler lives. In this way they could think without the distraction of a physical body. Unlike the cogitors, the cymeks motivation was to extend their lives to maintain tyrannical control over their empire.
The original cymeks were once a group of twenty ambitious young humans who saw the stagnation of the empire and realized that their small band could take control of it with the aid of machines. This group was called the Titans, after the Titans of Greek mythology. They all took new names after famous historical and mythological figures, most notably Agamemnon, Ajax, Barbarossa, Dante, Hecate, Juno, Tlaloc and Xerxes.
The Titans managed to retain power for a hundred years before Xerxes, one of the Titans, delegated the entirety of his authority to autonomous thinking machines. Networks of these machines became ever more intelligent and powerful, eventually taking control of his planet and forming the first Omnius computer. The Omnius spread from planet to planet until it controlled all of the Titans' holdings even before any of them understood what had taken place. The Titans and the neo-cymeks — new, disembodied soldiers not of the original 20 Titans, recruited from humans living on Omnius-controlled worlds (aka Synchronized Worlds)— were used by Omnius in battle, since they more fully understood human strategy and thought processes.
A small group of worlds, called the League of Nobles, resisted the initial Titan rebellion and remained free from first the Titans and then the thinking machines. It is on these planets that the Butlerian Jihad began, a war which expelled all semblance of artificial intelligence from the empire. During this period, many organizations developed to supply the skills needed to replace computers, including the Spacing Guild, the Mentats, and the Bene Gesserit. The formation of these organizations were aided by the discovery of the Holtzman effect and melange.