Military history of the Crusader states
The Seljuk–Crusader War began when the First Crusade wrested territory from the Seljuk Turks during the Siege of Nicaea in 1097 and lasted until 1128 when Zengi became atabeg of Aleppo. At the latter date, the chief threat to the Crusaders from the east and north became the Zengids. The conflict was generally fought between European Crusaders and the Seljuk Turks and their vassals. The Muslim Syrian emirates occasionally allied themselves with the Christians against rival states.
Criticism of Islamism
Lewis argues that any traumatization from the Crusades felt by Muslims surely would pale in comparison to what European Christendom felt from Islam. The Crusades started in 1096 and the Crusaders lost their last toe-hold when the city of Acre, was taken less than two hundred years later in 1291, whereas Europe felt under constant threat from Islam, "from the first Moorish landing in Spain [711] to the second Turkish siege of Vienna [1683]."