Excerpt from “The Zensunni Schism: A History” by Princess Irulan

The exile of the Zensunni is an event buried in history. The schism between the warlike teachings of Maometh Saari and the Catholic philosophical leanings of Ali Ben Ohashi* led to a great exodus from Old Terra.
The Zensunni were a persecuted people wherever they went. Space travel being limited to slowships and the presence of the infinite void heightened the strangeness of those who spent time there.
On every planet, the Zensunni found disdain – simple indifference, to military blockades, to violent raids and the slavery.
Like a tree shedding leaves as winter comes, so too did the Zensunni shed their weak and their infirm – until all that remained was a core of hardwood.
Zensunni philoshopy has spread across the Imperium – their wandering influenced so many of the worlds they touched – but we can only speculate as to where the final, hardened core of the Zensunni ended up.
*There are some sources who claim that his second wife, Nisai, was actually the mind behind the philosophy, while Ali Ben was only a mouthpiece.