求十字军东侵的历史背景，过程及影响（用英语回答 谢谢～））

The Christian Crusades
1095-1291
Since the time of Constantine, Christians had gone on pilgrimages to the Holy Land. Even though Moslems had ruled Jerusalem since 638, Christians were still allowed to visit the city. By the 11th century, however, the situation had changed. Just as the number and frequency of pilgrimages to Jerusalem was at new peaks, the Seljuk Turks took over control of Jerusalem and prevented pilgrimages.

The First Crusade
Pope Urban II (1088-1099, see art below) was responsible for assisting Emperor Alexus I (1081-1118) of Constantinople in launching the first crusade. He made one of the most influential speeches in the Middle Ages, calling on Christian princes in Europe to go on a crusade to rescue the Holy Land from the Turks. In the speech given at the Council of Clermont in France, on November 27, 1095, he combined the ideas of making a pilgrimage to the Holy Land with that of waging a holy war against infidels.1

Dr. E.L