Zensunni was a religious belief system prominent with many cultures spread across the Known Universe, especially those descended from disadvantaged and enslaved peoples.
Little is known of the evolution of the Zensunni faith. What is beyond doubt is that the Zensunni belief was an amalgam of two ancient religions: Sunni Islam and Zen Buddhism.
They were followers of a schismatic sect that broke away from the teachings of Maometh (the so-called "Third Muhammed") about 1381 BG. The Zensunni religion is noted chiefly for its emphasis on the mystical and a reversion to "the ways of the fathers." Most scholars name Ali Ben Ohashi as leader of the original schism but there is some evidence that Ohashi may have been merely the male spokesman for his second wife, Nisai .
Later, the Zensunni predisposition was manipulated by the Bene Gesserit, via their Missionaria Protectiva arm and Panoplia Propheticus strategy, for their own political objectives. One of the most prominent homes of Zensunni beliefs, Arrakis, was of particular interest in this regard. The exclusivity of the critical Spice Melange on the planet made the resident Fremen, staunch followers of Zensunni, of natural interest to the Bene Gesserit.
The emergence of the powerful Paul Atreides, and his adoption of Fremen ways, gave Zensunni beliefs a dramatic new popularity. After his ascension to Emperor Paul embarked on a ferocious jihad that brought great violence and turmoil. The stark contrast of these actions vis-à-vis pacifist Zensunni beliefs was not lost on some of the faithful.
- Dune, Termiology of the Imperium, page 345