The thing about the virgins (who are, remember, sewn shut, and you get to "open them like a flower") may or may not have been invented by the Hashishim/assassins (kinda like the Spanish Inquisition), but the concept remains as an available bribe to fanatics to this day. In the particular West African (mostly Moslem) country where I grew up it was a joke among people kind of like Christians might joke about hair shirts - a known mark of the fanatic and considered rather funny/antiquated/quaint. That's because it WAS in the mythology, even if it wasn't in the Koran. As was the bit about dying killing Infidels being good for going to Heaven; I think it had mutated into The more you kill the more virgins you get.