Explanation: Children’s Crusade, popular religious movement in Europe during the summer of 1212 in which thousands of young people took Crusading vows and set out to recover Jerusalem from the Muslims. Lasting only from May to September, the Children’s Crusade lacked official sanction and ended in failure; none of the participants reached the Holy Land. Nevertheless, the religious fervor it excited helped to initiate the Fifth Crusade (1218). It was arguably the first European youth movement.