>>16248061
It's funny because the Hashashins (where the word Assassin comes from) were a Shia Muslim sect that were into the occult and, of course, assassination. They were widely feared.
The crusaders learned of this and formed their own version - called the Knight's Templars, which later evolved into Freemasonry and Jesuits. The Jesuit method of deception and assassination is very much similar to how the Muslims did it.
tl;dr the inspiration for the Knight's Templars were the Arab assassins.