The Crusades were a series of religious wars between Christians and Muslims started primarily to secure control of holy sites considered sacred by both groups. In all, eight major Crusade expeditions—varying in size, strength and degree of success—occurred between 1096 and 1291. The costly, violent and often ruthless conflicts enhanced the status of European Christians, making them major players in the fight for land in the Middle East.

By the end of the 11th century, Western Europe had emerged as a significant power in its own right, though it still lagged behind other Mediterranean civilizations, such as the Byzantine Empire (formerly the eastern half of the Roman Empire) and the Islamic Empire of the Middle East and North Africa.

However, Byzantium had lost considerable territory to the invading Seljuk Turks. After years of chaos and civil war, the general Alexius Comnenus seized the Byzantine throne in 1081 and consolidated control over the remaining empire as Emperor Alexius I.

In 1095, Alexius sent envoys to Pope Urban II asking for mercenary troops from the West to help confront the Turkish threat. Though relations between Christians in the East and those in the West had long been fractious, Alexius’s request came at a time when the situation was improving.