Ampullae were miniature holy water flasks. They would be purchased at a shrine, filled with holy water and the top crimped shut. They were then carried home to await a time when the water’s miracle working powers could be put to good use, to cure a sickness for instance. The water from Canterbury, it was claimed, contained the blood of Becket. It is easy therefore to appreciate the importance to medieval minds of this type of souvenir. They were usually worn either sewn to the hat or suspended around the neck.
Original found in Salisbury.