Akko fell to the Egyptian Mamelukes (freed slaves of Turkish/Circassian origin) in 1291, bringing to an end the Crusader period.
The Crusader period was brought to an end by the Egyptian Mamelukes. 
mnli hypothesis: The Crusader period was brought to an end by the Egyptian Mamelukes.  premise: Akko fell to the Egyptian Mamelukes (freed slaves of Turkish/Circassian origin) in 1291, bringing to an end the Crusader period.