Feast Of The Assumption
The great French nobles and their trained armies of knights were not the first to undertake the journey towards Jerusalem.
Urban had planned the departure of the crusade for 15 August 1096, the Feast of the Assumption, but months before this a number of unexpected armies of peasants and petty nobles set off for Jerusalem on their own, led by a charismatic priest named Peter the Hermit of Amiens. Peter was the most successful of the preachers of Urban's message, who developed an almost hysterical enthusiasm among his followers, although he was probably not an "official" preacher sanctioned by Urban at Clermont. A century later he was already a legendary figure; William of Tyre believed that it was Peter who had planted the idea for the crusade in Urban's mind (which was taken as fact by historians until the nineteenth century). It is commonly believed that Peter led a massive group of untrained and illiterate peasants who did not even have any idea where Jerusalem was, but in fact there were many knights among the peasants, including Walter the Penniless.
The Assumption of Mary is the traditional belief held by Christians of the Roman Catholic, Eastern Orthodox, Oriental Orthodox, and some Protestant churches such as Lutheranism and Anglo-Catholic Anglicans that the Virgin Mary at the end of her life was physically taken up into heaven. The Roman Catholic Church teaches as dogma that the Virgin Mary, "having completed the course of her earthly life, was assumed body and soul into heavenly glory." This means that it claims that Mary was transported into Heaven with her body and soul united. This doctrine was dogmatically and infallibly defined by Pope Pius XII on November 1, 1950, in his Apostolic Constitution Munificentissimus Deus. The feast day recognizing Mary's assumed passage into Heaven is celebrated as The Solemnity of the Assumption of the Blessed Virgin Mary by Roman Catholics, and as the Dormition by Orthodox Christians. In those denominations that observe it, the Assumption is a major festival, commonly celebrated on August 15. This is a Holy Day of Obligation in many Roman Catholic jurisdictions.
Wikipedia: First Crusade
Wikipedia: Assumption Of Mary