I had to Google this. Here's a Wiki P link: https://en.wikipedia.org/wiki/Butlerian_Jihad https://en.wikipedia.org/wiki/Butlerian_Jihad It's from Frank Herber

I had to Google this. Here's a Wiki P link: https://en.wikipedia.org/wiki/Butlerian_Jihad https://en.wikipedia.org/wiki/Butlerian_Jihad It's from Frank Herbert's Dune :( Sad because I read this series (all six, I kid you not!! 1,2,6 are good 3,4,5 not so good) 25 years ago nearly and I had forgotten this specific detail. Time is indeed a cruel mistress and thanks for making me feel old :)