ALEXANDER LESLEY. - Jesuit, liturgist, born in the county of Aberdeen (Scotland) on 7 Nov. 1694, died in Rome on 27 March 1758. He successively taught at Sora and Ancona, then Greek at the Roman College and philosophy at the Illyrian College in Loreto. In 1728 he was sent to Scotland. In 1734 he is found again in Italy, professor first at Tivoli, then at the Scottish College, where he was also prefect of studies. From 1746 to 1749 he taught moral theology at the English College.
In 1749 he had been associated with Fr. Manuel de Azevedo in the publication of the Thesaurus liturgicus, a work announced in 13 volumes in-folio. Of this collection, L. published in Rome in 1755 the Missale mixtum secundum Regulam beati Isidori dictum Mozarabes, a reprint of the Mozarabic Missal published in Toledo in 1500 by order of Cardinal Ximenes, enriched with an important preface and valuable notes. The same work prepared for the Mozarabic Breviary and many other dissertations of a numismatic and lapidary character remain in manuscript.