The Children's Crusade is the name given to a Crusade by European Christians to expel Muslims from the Holy Land said to have taken place in 1212. The traditional narrative is likely conflated from some factual and mythical notions of the period including visions by a French boy and a German boy, an intention to peacefully convert Muslims in the Holy Land to Christianity, bands of children marching to Italy, and children being sold into slavery.
A study published in 1977 casts doubt on the existence of these events, and many historians came to believe that they were not (or not primarily) children but multiple bands of "wandering poor" in Germany and France, some of whom tried to reach the Holy Land and others who never intended to do so. Early versions of events, of which there are many variations told over the centuries, are largely apocryphal.
The variants of the long-standing story of the Children's Crusade have similar themes. A boy began preaching in either France or Germany claiming that he had been visited by Jesus and told to lead a Crusade to peacefully convert Muslims to Christianity. Through a series of portents and miracles he gained a considerable following, including up to 30,000 children. He led his followers south towards the Mediterranean Sea, in the belief that the sea would part on their arrival, allowing him and his followers to march to Jerusalem, but this did not happen. They were sold to two merchants (Hugh the Iron and William of Posqueres) who gave free passage on boats to as many of the children as were willing, but then they were either taken to Tunisia and sold into slavery by the merchants, or died in a shipwreck on San Pietro Island off Sardinia during a gale. Some may have failed to reach the sea, dying or giving up from starvation and exhaustion. They were betrayed by some of the adults in their group.
According to more recent researchers there seem to have actually been two movements of people (of all ages) in 1212 in Germany and France. The similarities of the two allowed later chroniclers to combine and embellish the tales.