A collection of pieces in organ tablature or score (most using mensural notation), said to be by John Bull and sometimes considered autograph. More recently most of the attributions have been doubted, and many of the canons have been found elsewhere (British Library R.M.24.c.14) attributed to Elway Bevin.
Probably copied by Gulielmus à Messaus. Once formed part of the bedroom library of the Emperor Leopold I.