Complex sentence: Shortly after the defeat of the Seventh Crusade, the Ayyubid Sultan Turanshah was assassinated at Fariskur and the Mamluks, those who defended Al Mansurah and prevented Louis IX from advancing to Cairo, grabbed power in Egypt ending the Ayyubid rule in that country.
Split into simpler sentences: Shortly after the defeat of the Seventh Crusade, the Ayyubid Sultan Turanshah was assassinated at Fariskur. The Mamluks, those who defended Al Mansurah and prevented Louis IX from advancing to Cairo, became the ruling power in Egypt, ending the Ayyubid rule in that country.