History of the Catholic Church
Pope Urban II started the First Crusade in 1095 when he received an appeal from Byzantine emperor Alexius I to help repel a Turkish invasion. Urban believed that a Crusade might help bring about reconciliation with Eastern Christianity. Encouraged by reports of Muslim atrocities against Christians, a series of military campaigns began in 1096. They were known as the Crusades. They were intended to return the Holy Land to Christian control. The goal was not permanently realized. Also, the Crusades left a legacy of mutual distrust between Muslims and Western and Eastern Christians. The sack of Constantinople during the Fourth Crusade left Eastern Christians resentful. In 2001, Pope John Paul II apologized to the Orthodox Christians for the sins of Catholics including the sacking of Constantinople in 1204.