Third islamic movement

The third islamic movement was a historical pre-butlerian religious movement connected with the figure of the prophet Maometh, the so-called "third Muhammed".The third islamic movement saw a shift towards syncretist mysticism which lay the foundation for Buddislam and it's various divisions including the Zensunni and Maometh Saari.

Dune Encyclopedia
According to The Dune Encyclopedia a historian named Lors Karden from Salusa Secundus had written a book on the topic: "A History of the Third Islamic Movement".