The philosopher Michel De Montaigne had some interesting thoughts on the use of assassins by Bedouin tribes in the Middle East.
The Assassins, who are a people dependent on Phoenicia, are considered by the Mahometans to be sovereignly devout and pure in morals. They hold that the surest way to merit paradise is to kill someone of an opposing religion. They therefore show contempt for all personal danger and are often to be found singly or on pairs, carrying out such profitable executions at the cost of their certain death, appearing before an enemy in the midst of his troops to ‘assassinate’ him – (it is from them that we have borrowed the word). Our own Count Raymond of Tripoli was killed this way in his own city.
Michel De Montaigne, Complete Essays, Volume II: 29, On Virtue. (16th Century)