The Children's Crusade was a disastrous popular crusade by European Christians to regain the Holy Land from the Muslims, said to have taken place in 1212. The crusaders left areas of Northern France, led by Stephen of Cloyes, and Germany, led by Nicholas. The traditional narrative is likely conflated from some factual and mythical events which include the 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. Many children were tricked by merchants and sailed over to what they thought were the holy lands but, in reality, were slave markets.
The Dutch historian Peter Raedts, in a study published in 1977, was the first to cast doubt on the traditional narrative of these events. Many historians came to believe that they were not (or not primarily) children, but multiple bands of "wandering poor" in Germany and France. A number of them tried to reach the Holy Land but others never intended to do so. Early accounts of events, of which there are many variations told over the centuries, are, according to this theory, largely apocryphal.
The variants of the long-standing story of the Children's Crusade have similar themes. A boy begins to preach in either France or Germany, claims that he had been visited by Jesus, who instructed him to lead a Crusade in order to peacefully convert Muslims to Christianity. Through a series of portents and miracles he gains a following of up to 30,000 children. He leads his followers south towards the Mediterranean Sea, in the belief that the sea would part on their arrival, which would allow him and his followers to walk to Jerusalem. This does not happen. The children are sold to two merchants (Hugh the Iron and William of Posqueres), who give free passage on boats to as many of the children as are willing. The pilgrims are then either taken to Tunisia, where they are sold into slavery by the merchants or else die in a shipwreck on San Pietro Island off Sardinia during a gale. A few may have failed to reach the sea, and die or give up from starvation and exhaustion. They had been betrayed by some of the adults in their group.