Fear of the Seljuk Turks, caused the emperor of Byzantine to ask Pope Urban ll for help. The pope called nobles and church leaders to a council in Clermont
Saladin freeing Jerusalem caused the Third Crusade
Crusaders surround Antioch in June 1098, after nine months Antioch fell to the Christians. In July 1099, Jerusalem surrendered to the Crusaders, and ended the First Crusade
Muslims started to band together and fought back the invaders. Together in 1144, they captured the capital of the northmost crusader kingdom, Edessa. In 1148, the king of France led an attack against the Muslims of Edessa but was defeated and sent running home.
The crusade was led by King Richard l of England. In the city of Acre of 1191, Richard's army forced the surrender of the town and killed 2,700 Muslim prisoners. In 1192, the two leaders signed a peace treaty, that would allow the Christians to keep a chain of cities along the coast of Palestine and allow Christian pilgrims access to Jerusalem.
In 1212, is the Children's Crusade, where thousands of peasant children marched. None of the crusaders managed to recapture Jerusalem, while the Muslims were going back the land they lost.
The Reconquista was a series of wars launched by the Christians to retake Spain and Portugal. The victory of the Christians forced the Muslims and Jews to either accept baptism as Catholics or leave. This victory ended any past friendship between the two religions.