The Shepherds' Crusade of 1251 was a popular crusading movement in northern France aimed at rescuing King Louis IX during the Seventh Crusade.
In 1249, Saint Louis IX of France went away on crusade, leaving his mother, Blanche of Castile, as regent during his absence. Louis was defeated and captured in Egypt. When news of this reached France the next year, both nobles and peasants were deeply distressed; the king was well-loved and it was inconceivable to them that such a pious man could be defeated by heathens. Louis sent his brothers to France to get relief, where despite the efforts of Blanche of Castile, it was seen that neither the nobility nor the clergy were helping the king.
One of the outpourings of support took the form of a peasant movement in northern France, led by a man known only as "the Master of Hungary." He was apparently a very old Hungarian monk living in France.
The Master claimed to have been visited by the Virgin Mary, who instructed him to lead the shepherds of France to the Holy Land to rescue Louis. His followers, said to number 60,000, were mostly young peasants, men, women, and children, from Brabant, Hainaut, Flanders, and Picardy. They followed him to Paris in May, where the Master met with Blanche of Castile. Matthew Paris thought he was an impostor, and that he was actually one of the leaders of the Children's Crusade from earlier in the century. Their movement in the city was restricted; they were not allowed to cross to the Left Bank, where the University of Paris was located, as Blanche perhaps feared another disturbance on the scale of the University of Paris strike of 1229.