"Catherine heard the voice telling her, "Have a medal struck after this model. All who wear it will receive great graces. They should wear it around the neck. Graces will abound for persons who wear it with confidence." So this was the mission entrusted to Catherine: to see to the making of this medal and sto spread its use. During 1830 and 1831 this vision of November 27 was repeated some six times to encourage Catherine in fulfilling her mission. She had to suffer much for this cause; first in trying to get the medals made, and then in trying to keep herself hidden, which she did for forty-six years till she died in 1876."
Church
St. Catherine Laboure
http://www.marys-touch.com/Saints/medal/medal.htm

