The history of medieval music has always rested on fragmentary sources, and polyphony in medieval England is no exception to this. Ernest H. Sanders and Peter M. Lefferts describe this as a ‘lamentable’ state of affairs: English polyphony is found plentifully in liturgical manuscripts and miscellanies, but is not the sole contents of any surviving codex between the Winchester Troper and Old Hall. 1 For evidence of the existence of large anthologies of polyphony in medieval England, we must instead look to fragments of these manuscripts that have been bound into or wrapped around other books. Sometimes these fragments are tiny, damaged or illegible: the reconstruction of a large source from such small fragments is often frustrated by the patchy survival of a manuscript that has been cut up, and the fact that fragments might be sewn or glued into a book, difficult to remove without damaging the host volume.