In 1984, he was appointed Prefect of the Vatican Library by Pope John Paul II. Boyle set about the digitization of the library's many manuscripts. Boyle employed women for the first time as part of the library's staff.[4] In 1987, he was made an Officer of the Order of Canada.[5]
In 1997, he was involved in a lawsuit regarding the legality of reproductions of Vatican manuscripts. Boyle was exonerated, but the case took its toll on his health.[6][7]
Boyle was living with emphysema and cancer and died on October 19, 1999. He is buried at the San Clemente al Laterano.[1]
Duggan, Anne J., Joan Greatrex, and Brenda Bolton, eds. Omnia disce: medieval studies in memory of Leonard Boyle, O.P. Aldershot, Hants, England; Burlington, VT: Ashgate, c2005. ISBN0-7546-5115-0
Roma, Magistra Mundi: Itineraria Culturae Medievalis. Mélanges offerts à Père L.E. Boyle à l'occasion de son 75e anniversaire, edited by Jacqueline HAMESSE (Fédération Internationale des Instituts d'Etudes Médiévales, 10/1-3). Louvain-la-Neuve: Fédération Internationale des Instituts d'Etudes Médiévales, 1998.
Stille, Alexander. Letter from Vatican City, Library Privileges, The New Yorker, 28 September 1998, p.43