On May 22, 1176, a murder attempt by the "Assassins" on Saladin occurred near Aleppo. This is an excellent history of the 'hashashun'. Here is short excerpt on the attempts on Saladin's life:
"One near victim was Saladin, Sultan of Egypt and Syria (r. 1174-1193 CE). Saladin, a Sunni Muslim, had earned the Assassins' wrath by publicly proclaiming that all Muslim heretics would be crucified. The Assassins responded in their tried and tested way. Twice, though, assassins failed to kill their target. First, in 1175 CE, a group of 13 failed to get close to their victim and the second time, in 1176 CE, four assassins only managed to pierce Saladin's cuirass and slash a cheek before they were butchered by the sultan's bodyguard.
Saladin responded emphatically to these attempts by first ravaging the countryside around Masyaf and besieging the castle for a week. Then the campaign was strangely abandoned. An explanation for this turnaround may have been the story that Assassins had stolen into Saladin's tent at night but, instead of killing him, they had left a knife under his pillow as a warning of what so easily might have been (Nur ad-Din, governor of Aleppo and Edessa from 1146-1174 CE, received a similar warning). An alternative version to this story, which comes from an Ismaili text, has an Assassin leave a poisoned cake under the Sultan's pillow with a sinister note saying 'you are in our power.'
Yet another version of the events has an emissary from the Assassins granted an audience with Saladin who stood safely behind two of his most trusted bodyguards. The emissary then asked the guards would they kill the sultan if he asked them to and they replied, 'certainly.' A little fanciful perhaps that the Sultan's entourage would be so infiltrated by Assassins but the morale of all three versions of the tale is clear: no person could escape the Assassins indefinitely if they had selected you as their target. Whatever the true version, Saladin got the message and negotiated a mutually beneficial non-aggression pact with the Assassin leader in Syria."