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 Europe
The Viking Age, a period of migrations of Scandinavian peoples, occurred from the late 8th century to the middle 11th century. The Normans, descendants of the Vikings who settled in Northern France, had a significant impact on many parts of Europe, from the Norman conquest of England to Southern Italy and Sicily. The Rus' people founded Kievan Rus', which evolved into Russia. After 1000 the Crusades were a series of religiously motivated military expeditions originally intended to bring the Levant back under Christian rule. The Crusaders opened trade routes which enabled the merchant republics of Genoa and Venice to become major economic powers. The Reconquista, a related movement, worked to reconquer Iberia for Christendom.