Children’s Crusade
Bands of youths and poor people set out from France and Germany for the Holy Land; most dispersed or starved, and some were said to have been sold into slavery.

Gustave Doré · Public domain · Source
A shepherd boy named Stephen is said to have led the French band and one Nicholas the German one. The Germans crossed the Alps to Italian ports, but when the sea did not part they broke up.
Sources are few and later legend is abundant. Whether the participants were really children, and whether some sailed from Marseille only to be sold as slaves, is debated. Many historians now see it as a popular pilgrimage movement of poor peasants and young people.