The article explores the heraldic, liturgical, hagiographical, and iconographic components of an illuminated Book of Hours ( c.1500) now in the Jesuit Archives in Montreal. Internal evidence points to Charles de Masmines, a member of a prominent Flemish family, as the manuscript’s first private owner (with unclear links to the Ghistelles family) and also to its last private owner, the Montrealer Pierre Bouthillier. The article examines the unusual presentation of the Masmines and Ghistelles coats of arms and discusses the manuscript’s rare use of the calendar, examines several prayers to protect against the Black Death, and identifies the illuminators of this codex as the Masters of Raphaël de Mercatellis.