This tale takes place in the first years of the 13th century, a time when Poitiers was surrounded by a city wall. Around Easter, one of the mayor's men happens to meet English authorities, and accepts -in exchange of a considerable amount of money- to deliver the city keys to them, once they have arrived in front of the gates.
When the moment comes, the traitor goes to rob the keys, but can't find them in their usual spot. Alerted, the mayor, in turn, starts searching for them with no more success. Since the unexplained disappearance is rather disturbing, the mayor goes to the church of Notre-Dame-la-Grande, with the intention of ringing the bells to call the citizens for help.
On arrival, the mayor is surprised and relieved to find the missing keys dangling in the hands of the sculpted Virgin Mary in the church choir! The miracle fortunately saved Poitiers from a dreadful fate. But meanwhile, the English troops, massed in front of the south city door, had not yet seen the worst of their troubles : above the wall, in a supernatural cloud, they suddenly see the Virgin and Child, accompanied by Saint Radegund and Saint Hilary -two Poitevan figures from early Christian times. It is said that the soldiers, struck with terror, kill themselves while running away in a melee.
To commemorate the event, a statue of the Virgin carrying the keys was placed in the choir of Notre-Dame-la-Grande, where visitors can still see it today. It used to be used in annual processions during the three Rogation-Days.