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.
History of the Jews and the Crusades
As the Crusades began, many Jews were in danger of being killed. There are documented accounts of how, as the Crusades spread and reached different towns and cities, Christians stood up and attempted to protect the neighboring Jews. In the German city of Trier, the local bishop attempted to protect the Jews. The bishop was still new to the city, however, and did not have the political power necessary to band the town together. In the face of the crusaders' attack, the local bishop abandoned his attempt to save the Jews and told them that "You cannot be saved—your God does not wish to save you now as he did in earlier day. Behold this large crowd that stands before the gateway of the palace", as well as forcing them to choose between conversion and removal from his palace.