Something extraordinary happened to the army of Edward III on Monday, April 13, 1360, as they camped in an open field near Chartres during the Hundred Years’ War.

According to the contemporary historian Jean Froissart, “During the time that the French commissioners were passing backwards and forwards from the king to his council, and unable to obtain any favourable answer to their offers, there happened such a storm and violent tempest of thunder and hail, which fell on the English army, that it seemed as if the world was come to an end. The hailstones were so large as to kill men and beasts, and the boldest were frightened.”

Some sources say that 1,000 men and 6,000 horses were killed. Possibly they died through cold rather than trauma; a London chronicle says the “day was a foul dark day of mist and hail, and so bitter cold that many men died for cold.”

Whatever it was, it shook Edward’s confidence. Froissart writes, “The king turned himself towards the church of Our Lady at Chartres, and religiously vowed to the Virgin, as he has since confessed, that he would accept of terms of peace.”