“Britten to Fischer-Dieskau, 1961: ‘Please forgive me writing to such a busy man as yourself — you can be sure that if I did not feel very strongly I should not be troubling you! … I am writing what I think will be one of my most important works. It is a full-scale Requiem Mass for chorus and orchestra … Peter Pears has agreed to sing the tenor part, and with great temerity I am asking you whether you would sing the baritone.'”