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.
Crusades
Minor Crusading efforts lingered into the 14thcentury, and several Crusades were launched during the 14th and 15th centuries to counter the expansion of the Ottoman conquest of the Balkans. In 1309 as many as 30,000 peasants gathered from England, north-eastern France, and Germany proceeded as far as Avignon but disbanded there. Peter I of Cyprus captured and sacked Alexandria in 1365 in what became known as the Alexandrian Crusade; his motivation was as much commercial as religious. LouisII led the 1390 Barbary Crusade against Muslim pirates in North Africa; after a ten-week siege, the Crusaders signed a ten-year truce.