This is one of the most important keyboard music manuscript from 16th century England. It is the earliest of four surviving MSS of this time, the others being those of Thomas Weelkes and Will Forster (BL) and the Fitzwilliam virginal book (Cambridge). The MS contains 42 works by William Byrd (1543-1623), copied by John Baldwin (completed on 11 September 1591) but with corrections thought to be by Byrd himself.