The Livre d’orgue de Montréal (Montreal organ book) is the largest extant manuscript of French organ music of the period of Louis XIV (reigned 1643−1715). Labeled “Pièces d’orgue” (Organ pieces) on the spine, the 540-page book is comprised of 40 separate quires, or collections of leaves. The book has no table of contents or indication of composer, but 16 of its 398 pieces have been attributed to Nicolas Lebègue (1631–1702), organist to the king in France. Among Lebègue’s pieces in the manuscript are the “Tierces ou cromhornes en taille” (Tierces or krummhorns in tenor) of 1676, the “Magnificat du 2me” (Magnificat of the second) of 1678, “Offertoire”(Offertory) and“Élévation”(Elevation) of 1685, and “Offertoire en F ut fa”(Offertory in F-flat major), a piece never published in Lebègue’s lifetime. In addition to Lebègue’s work, the manuscript contains six masses, eleven Magnificats sung at Vespers, nine other suites of pieces that could be used as Magnificats, three Te Deums, and a Pange lingua. The manuscript bears the mark of two previous owners: on the outside front cover, “J.J. Girouard 1847,” and on the inside front cover, “Girard 1724.” Jean Girard (1696–1765) trained as a church musician at the Sainte-Chapelle in Bourges. He entered the Sulpician Seminary in Bourges or Paris in 1720 but was never ordained as a priest. He instead requested permission to travel to Montreal in 1724, where he became the organist at the parish of Notre-Dame. He took with him, along with Guillaume-Gabriel Nivers’s Premier Livre d’orgue (First organ book) and Traité de la Composition de musique (Treatise on the composition of music), this manuscript of French organ pieces. In the 19th century, Jean-Joseph Girouard (1794–1855), a notary, music lover, and intellectual leader of the 1837 Rebellion, acquired the manuscript from the Sulpicians (the Catholic society to which Girard belonged).