Built at the behest of Richard Beauchamp, 13th Earl of Warwick (1382–1439), the Beauchamp Chapel at the Collegiate Church of St Mary, Warwick, is a remarkable survival of fifteenth-century architecture, sculpture, and—above all—stained glass. These windows are well known to organologists for their depictions of instruments and performance practice; they also provide useful information about chant and polyphony in fifteenth-century England by preserving fragments of neumatic notation.
Over the centuries craftspeople have restored damaged windows, and, lacking the requisite musical training, they often left replacement staves blank; but in two cases nonsense neumes were devised, supplying consistent-looking décor that most observers would never suspect was counterfeit.
This according to Alexandra Buckle’s “Fit for a king: Music and iconography in Richard Beauchamp’s chantry chapel” (Early music XXXVIII/1 (2010), pp. 3–20).