Byrd's double life, in public a member of Queen Elizabeth I's Chapel Royal in a newly Protestant England, in private a covert Catholic, directly shaped his music. Grand works such as the Great Service are among the glories of the English choral tradition. In contrast, the three Latin masses set here, long neglected, were for amateur, chamber performance in hidden Catholic communities. Westminster Cathedral Choir may sing them with more splendour and finesse than Byrd himself would have expected, yet the results are uplifting and moving. It's no slight to these musicians to say the disc is worth buying for the Byrd scholar John Milsom's incomparable notes: a masterly encapsulation of Tudor church music history in a few dense pages.