 This was closely followed by the deaths of the Seljuk Sultan Malik-Shah and the Fatimid khalif, Al-Mustansir Billah.The Islamic historian Carole Hillenbrand has described this as analogous to the fall of the Iron Curtain in 1989 with the phrase "familiar political entities gave way to disorientation and disunity".The confusion and division meant the Islamic world disregarded the world beyond; this made it vulnerable to, and surprised by, the First Crusade.