The 500 years after the fall of Rome to the Germanic Vandals is often thought of as Europe's Dark Ages. The period from about A.D. 476 to 1000, the Dark Ages originally referred to the lack of Latin literature produced in the period. Later, the term Dark Ages was expanded to cover a dearth of cultural advances in general. The Middle Ages refers to the period between the Dark Ages and the Renaissance (400 to 500 years later); some Renaissance writers called the Renaissance the modern age.
The most historically memorable though highly debated phenomenon of the Middle Ages was the crusades, military campaigns carried on in the name of Jesus and under the banner of his cross, under papal sanction, from the eleventh through thirteenth centuries. The first of these was launched in 1095 by Pope Urban, inspired by a letter from Emperor Alexius Comnenus in Constantinople to Robert, Count of Flanders, asking for aid to stop the persecution of pilgrims to the Holy Land by Muslims who were conquering more and more of the empire.
Crusaders Take Jerusalem
Count Robert forwarded the letter to the pope, who used it to raise an army to travel to the Holy Land and take Jerusalem and the Holy Land back from the Muslims. An army of both knights and peasants traveled over land and sea to reach Jerusalem, took it in 1099, and established a Kingdom of Jerusalem ostensibly under patronage of Jesus Christ, their professed High King.
The crusades arose from pietistic fervor that swept Europe at this time coupled with a desire of thousands of people to make radical changes in their poor and drab lives. The First Crusade was also boosted by its proximity to the change of millennia, and events in the heavens, including the appearance of a comet and a meteor shower.
A dozen or more crusades followed in this period, depending on how they are counted (some are considered subcrusades of larger or earlier ones), but nine are identified by number. As a whole, the crusades can be called the most clearly defined holy war in Christian history, in the sense that the crusaders — mainly uneducated peasants — considered themselves defenders of the sovereignty of Jesus Christ against a newer competing religious movement.
A subtext of the holy war was gaining papal superiority over the Orthodox churches in the east, which was temporarily achieved by the sacking of Constantinople in 1204 during the Fourth Crusade. Byzantine ruler Michael VIII Palaeologus recaptured Constantinople in 1261.
Only the First Crusade succeeded at achieving its goal, gaining control of Jerusalem. The general view of history, including that of the modern Catholic Church, is that the crusades were a misapplication of religious zeal, trying to win infidels in a way that was against the teachings of Jesus.