(CNN) -- The heart of a 900-year-old saint has vanished from Christ Church Cathedral in Dublin, Ireland, police and the Cathedral said.
St. Laurence O'Toole's heart was kept in a heart-shaped wooden box in a cage bolted to a wall in Saint Lauds Chapel, Irish police said.
It disappeared between Friday evening and Saturday noon, police said.
Adding to the mystery, there was no sign of a break-in or of damage, police told CNN.
Nothing was taken from the chapel other than the heart, although Irish media said there were gold candesticks and other valuables there.
Cathedral staff called the disappearance of the relic "truly awful and strange" and said they were "shocked and saddened."
St. Laurence O'Toole was born in 1128, lived until 1180, and was made a saint in 1225, according to the Catholic Encyclopedia.
Catholics often preserve body parts from saints, believing they should be venerated. When Pope John Paul II was declared "blessed" -- a step below sainthood -- last year, a vial of his blood was displayed as a relic.