The canon is arranged for three vocal parts
The tune is the imitation plainchant 'Alleluia' Britten added to 'Hodie Christus natus est' sent to him by Alec Robertson in 1943 for use as the 'Procession' and 'Recession' in A ceremony of carols (Mar-Oct 1942).
Composed for Dear Alec . . ., a tribute for his eightieth birthday from friends known and unknown (Stanbrook Abbey Press, 1972), a limited edition published as a tribute to Alec Robertson, which included a facsimile of the autograph of the canon. Britten was invited to contribute by Donald Beswick in December 1970 but it was not until the autumn of 1971 that the three-part canon was composed.