Joan II, Duchess of Berry's Dress

Origin
At Le Bal des Ardent, Louis I of Orléans' Torch set fire to four of the dancers. King Charles IV was away from the other dancers and was protected from the flames by Duchess Joan II of Berry who shielded the King with the train of her dress.

Effects
The dress is fireproof and could not catch fire by conventional or magical means. But anyone who is wearing the dress would become sterile.