1923 – He was born in Ballintra, County Donegal, Ireland on the 13th of November.
1940 – Boyle spent some years in Tralee following the tragic death of his older brother John.
1943 – Leonard was educated in Gaelic and entered the Dominican Order.
1949 – He was ordained a priest having received his doctorate in Oxford.
1961 – He taught at the Pontifical Institute of Mediaeval Studies, and at the Centre for Medieval Studies at the University of Toronto.
1984 – He was appointed Prefect of the Vatican Library by Pope John Paul II.
1987 – He was made an Officer of the Order of Canada.
1999 – He died on the 25th of October.