Boyle was born in Donegal in 1923. He hardly knew his father, who emigrated to the United States to work on the railroads soon after he was born. He was brought up by his mother, and got his schooling, rather improbably, from the Trappist Fathers. He entered the Dominican order in 1943, and was ordained priest in 1949.
Naturally learned, he gravitated to Blackfriars in Oxford, and began work on the Oxford scholastics, with W.A. Panton as his supervisor. At the same time, he discovered an aptitude for palaeography, and was one of many who came under the spell of Richard Hunt, Keeper of Western Manuscripts at the Bodleian Library. He took his DPhil in 1956, and in the same year moved to Rome as Professor of the History of Theology at the Angelicum.
In 1961 he was called by Reginald O'Donnell to teach at the Basilian Fathers' Seminary at Toronto, and was appointed a Fellow of the Pontifical Institute of Medieval Studies and Professor of Palaeography and Diplomatic in the University of Toronto, a post he was to hold for over 20 years. This might seem an ivory tower of scholarship, remote from the more ordinary walks of life. Boyle made it something entirely different. His vitality and warmth, even more than his learning, brought students to the institute from all over the world. His classes were packed, and no one who attended them will forget the humour and sense of excitement that made the dry bones of ancient texts spring to life. Anything from techniques of abbreviation to the long-forgotten cross-fire of medieval disputations engaged his lively mind and gift of vivid exposition.
His influence overflowed the bounds of his position. The Center for Reformation and Renaissance Studies at Victoria Collegewas only one of the many local institutions that benefited from his help. The Bergendal Collection of medieval text manuscripts at Toronto, a remarkable assemblage to have been put together in recent times, came into being at his suggestion.
Besides his scholarly and teaching concerns, Boyle was even more loved and admired for his pastoral gifts. Any one in any sort of doubt, uncertainty or misery was apt to turn to him for help and consolation. Comfort he could provide - his sense of humour was irresistible - but he also had a wonderful knack of finding a job, a way out of apparently insuperable difficulties, that provided the practical answer to the problems that were brought to him.
Somehow, he also found time to produce a string of learned articles and books. In 1970, he was made general editor of the long-running Calendar of Documents in Papal Registers Relative to Great Britain and Ireland for the Rolls series. He wrote an authoritative Survey of the Vatican Archives, familiar from his Roman days, in 1972, and published a history, The Community SS Sisto and Clemente, in 1977. He put all scholars of his own special discipline in his debt with Medieval Latin Palaeography: a bibliographical introduction (1984), a modest title for a substantial reference book. The most important of his works, Pastoral Care, Clerical Education and Canon Law, 1200-1400 (1981), brought together his wide reading and deep understanding of three enormous and only partly overlapping aspects of the Church in the Middle Ages; only someone with his breadth of knowledge and personal familiarity with all three, now as then, could have achieved this synthesis.
In 1984 he was appointed Prefect of the Vatican Library, with a brief to open up an institution not well known for its hospitality to visitors. It was only open in the mornings, plus an occasional hour or two in the evening; favoured and trusted readers were sometimes allowed to stay on in the afternoons, but only on pain of being locked in, with no escape for a breath of fresh air, until released in the evening.
Boyle changed all that. The doors were flung open from morn till night. Scholars were welcomed from all over the world; often he welcomed them himself in person. He delighted in showing larger groups its treasures. His telephone and fax machine were constantly busy, and he himself often hoarse from having to talk too much. The staff, at first apprehensive, were won round by his patent goodness, and came to try and protect him from the over-exposure to which his hospitality subjected him.
Most of his visitors appreciated not only his generosity but also the strain that it caused. I remember writing in advance to ask if I might collate the Vatican copy of a book, expecting to do so in the Reading Room. Instead I found it laid out for me on a table in the Prefect's Room and I witnessed the constant flow of visitors, the endless telephone calls, visits from workmen and Vatican functionaries, that filled his day. Not all were as scrupulous. Professor Anthony Melnikas from Columbus, Ohio, betrayed his trust by stealing leaves from a Vatican manuscript, as well as others from Toledo. But this was a small setback compared with the great benefit that the scholarly world derived from his regime.
In 1997, however, disaster struck. Boyle had always welcomed scholarly publication of the Vatican's riches, and had already engaged Belser Verlag, who published some excellent facsimiles. Boyle's predecessor and now superior, Cardinal Stickler, was tempted by an offer from California to reproduce Vatican manuscripts, and to digitise them so that they could be made available as CDs or on the world-wide web, in exchange for an exclusive licence. Boyle was instructed to sign a contract for this. But it soon became clear that this was ultra vires, and doubts were cast on the ability of the California firm to deliver what it had undertaken. Boyle was made the scapegoat, and relieved of his post.
He made no recrimination, and preserved a rigid silence about the affair. Subsequently, an article appeared in The New Yorker. It was one-sided, since most of its information came from California and none from Rome, but it at least made clear that Boyle's integrity was above suspicion.
These anxieties brought Boyle to the point of exhaustion. His lean, sallow frame got thinner and thinner, but he seemed to have inner resources of strength, physical as well as spiritual and intellectual. His room in the Collegio San Clemente, his residence while Prefect, remained full of work, and he had appeared to be recovering his energy. But in early October it became clear that he had not long to live (he suffered from emphysema, to which cancer was now added). His colleagues sang the Salve Regina for him at 5 o'clock on Sunday 18 October, and the following day he died. Open-handed and open-hearted in life and in scholarship, as humble as generous, he had, like Pius XI, an inner reserve of sanctity.
Leonard Eugene Boyle, priest and palaeographer: born Ballintra, Co Donegal 13 November 1923; ordained priest 1949; Prefect, Vatican Libray 1984-97; President, Comite Internationale de Paleographie 1985-95; President, Federation Internationale des Instituts d'Etudes Medievales 1988; died Rome 19 October 1999.