The crusades started with the plea for help of Emperor Alexios I and Pope Urban's call for the reconquest of the Holy Land in 1095/96. But said territory had fallen under Muslim rule way back in the 7th century. So why didn't a crusade happen at an earlier date? Or had there been similar attempts (other than by the Byzantines)? If there was no one interested in a crusade earlier where did the "sudden" enthusiasm in the 11th century come from?