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.
Reconquista
The Crusades, which started late in the 11th century, bred the religious ideology of a Christian reconquest, confronted at that time with a similarly staunch Muslim Jihad ideology in Al-Andalus by the Almoravids, and to an even greater degree by the Almohads. In fact, previous documents from the 10th and 11th centuries are mute on any idea of "reconquest". Propaganda accounts of Muslim-Christian hostility came into being to support that idea, most notably the "Chanson de Roland", a fictitious 11th-century French version of the Battle of Roncevaux Pass (778) dealing with the Iberian "Saracens" ("Moors"), and taught as historical fact in the French educational system since 1880.