[Skybird]

The Mongolian storm on Baghdad was a wipeout of the city, that's why. The city was destroyed, the population more or less annihilated. On a side note, many of that time's promising "alternative thinkers" and "mystics" of name of the Islamic world were killed there. That's why until today Islam has not really an esoteric, mystic tradition of real size and importance. It'S roots got killed by the Mongolian attack. Sufism later on never became more than just a curiosity that today attracts tourists. The Mongols had gotten some trouble by the order of the Assassines, and solved the problem finally by wiping out their order without making compromises (something all others who were terrorised by them were unfit to achieve). Afterwards they wanted to execute an example against those factions that once were allied or in support of them. The Abassides' caliphate in Persia was top on their list, therefor.