St Isidore's College in Rome, belonging to the Irish Franciscan Province, preserves a manuscript from the end of the fifteenth century, MS I/88, which in addition to various Latin theological and liturgical texts contains many Italian laude and Latin hymns, nine of which have music. The two laude are Vergene madre pia and O Jesù dolce, o infinit'amore, for two voices; of the seven Latin hymns, three are for three voices, two for two, and one is monodic. All these pieces are also found in other sources except for the two-voice hymn Hic est Christus, which appears to be an unicum. This new source, in conjunction with those already known, not only permits us to understand the history of the manuscript tradition of these texts and their music, but also is very interesting in that it provides a new witness for the diffusion of the lauda in Franciscan circles and the particular ways in which it was transmitted – not in official liturgical books but within miscellaneous volumes of texts and prayers of various kinds, uses, and provenance. Finally, from a musical point of view the Franciscan manuscript confirms the use of so-called ‘simple polyphony’ throughout the fifteenth century side by side with more complex polyphony in the Franco-Flemish tradition.