How long has the middle east been in turmoil... well, since long before this. But, it didn't help!!
During the First Crusade, Christian knights from Europe capture Jerusalem after seven weeks of siege and begin massacring the city’s Muslim and Jewish population.
Beginning in the 11th century, Christians in Jerusalem were increasingly persecuted by the city’s Islamic rulers, especially when control of the holy city passed from the relatively tolerant Egyptians to the Seljuk Turks in 1071. Late in the century, Byzantine Emperor Alexius Comenus, also threatened by the Seljuk Turks, appealed to the West for aid. In 1095, Pope Urban II publicly called for a crusade to aid Eastern Christians and recover the holy lands. The response by Western Europeans was immediate.
The first crusaders were actually undisciplined hordes of French and German peasants who met with little success. One group, known as the “People’s Crusade,” reached as far as Constantinople before being annihilated by the Turks. In 1096, the main crusading force, featuring some 4,000 mounted knights and 25,000 infantry, began to move east. Led by Raymond of Toulouse, Godfrey of Bouillon, Robert of Flanders, and Bohemond of Otranto, the army of Christian knights crossed into Asia Minor in 1097.