The Crusades (1095–1291)

In November 1095, Pope Urban II preached a sermon at Clermont-Ferrand in France to launch the First Crusade. The aim was to aid the Christians of the East and return to Christian control the Holy Sepulcher, the church in Jerusalem said to contain the tomb of Christ. Absolution from sin and eternal glory were promised to the Crusaders, who also hoped to gain land and wealth in the East. Nobles and peasants responded in great number to the call and marched across Europe to Constantinople, the capital of the Byzantine empire. With the support of the Byzantine emperor, the knights, guided by Armenian Christians, tenuously marched through Seljuq-controlled territories in modern Turkey and Syria to Jerusalem. In June 1099, the Crusaders began a five-week siege of Jerusalem, which fell in July 1099. The Crusaders then took over many of the cities on the Mediterranean coast and built a large number of fortified castles all over the Holy Land to protect their new territories.

In 1147–49, the Second Crusade, championed by the abbot Bernard of Clairvaux, attempted to take Damascus in Syria. The campaign was a dismal failure because the Muslims had regrouped. Led by Salah al-Din (Saladin), Muslim forces advanced across Syria and finally retook Jerusalem in October 1187. By the end of the Third Crusade (1189–92), however, Crusader forces had gained Cyprus and the city of Acre. With each crusade, relations between the Byzantines and the Western forces became more estranged.

The Fourth Crusade set out in 1202 with Egypt as its goal. After choosing sides in a dynastic dispute in Byzantium, however, the Crusades turned their seige upon Byzantium's capital, Constantinople, to collect an enormous sum of money that had been promised for their earlier support. The city was sacked in 1204, its rich treasures divided between the Venetians, the French, and other Crusaders. The Latin Empire of Constantinople was established with Baldwin of Flanders as emperor. In 1261, the Byzantines regained the city.

Successive crusades were launched to the Holy Land. The Seventh and Eighth Crusades, in 1248 and 1270, were sponsored by Louis IX, who died in Tunisia. In 1291, the Crusader city of Acre fell, and the era of Latin Crusader kingdoms ended. Calls for new crusades over the next centuries were increasingly ignored.