Sheppard may have begun composing as early as 1534 but much of his early music has not survived, with the majority of the Latin works which remain seeming to date from the reign of Mary I (1553-58). In his responsorial settings (where elaborate counterpoint is often woven around a slow-moving cantus firmus) he produces music of the highest technical skill, which rivals the Latin works of his more illustrious contemporary, Thomas Tallis. Only a small number of his English anthems remain, and O God be merciful unto us, and bless us – a joyful setting of the Anglican canticle Deus misereatur now available for the first time – is a welcome addition to his published output. Most of Sheppard's anthems were written in the 1540s and this work displays many of the characteristics of the English music of that period. The entire text of Psalm 67 is supplemented by a concluding Gloria cleverly adapted from earlier material, and the music is mostly based upon repeated sections of imitative counterpoint.