On Francois Couperin's own evidence we know of the loss of the six Leçons de Ténèbres required to complete the set of nine. How much more of his occasional music remains to be found is beyond conjecture, but the identification by the author of a number of his motets, hitherto unknown, in the library at St. Michael's College at Tenbury considerably augments the corpus of Couperin's sacred music. The six volumes containing these motets form part of the rich collection of some 450 volumes of music copied by Philidor and his team for the Comte de Toulouse, son of Louis XIV and Mme. de Montespan, in the first years of the eighteenth century. The greater part of the collection passed into the hands of the founder of St. Michael's College, the Reverend Sir Frederick Gore Ouseley, in the 1850s, while some 60 books from the original Toulouse collection were added in 1934, too late to be listed in the published catalogue. Among this second acquisition was the set of Couperin volumes, and their absence from the catalogue is no doubt the reason for their long obscurity. Furthermore, Fellowes's manuscript catalogue of additions at the library gives an incomplete list of contents.