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.
Children's Crusade
P. Alphandery (1916) first published his ideas about the crusade in 1916 in an article which was later published in book form in 1959. He considered the story of the crusade to be an expression of the medieval cult of the Innocents, as a sort of sacrificial rite in which the Innocents gave themselves up for the good of Christendom; however, he based his ideas on some of the most untrustworthy sources.