The Book of Common Prayer was an argument in book form: that the worship of the church should be understood by the people praying it. Thomas Cranmer's 1549 volume replaced the Latin service books of the medieval English church, missal, breviary, manual and more, with one book in English, and its title announced the program, prayer held in common. The monastic round of eight hours was folded into two public offices, Morning and Evening Prayer, built on psalms read in course, scripture read through in a year, and the great canticles; the litany, which Cranmer had already Englished in 1544, gave the church a processional prayer of supplication; the communion service rendered the Mass into English with a reformed theology; and the occasional offices carried the book into every parishioner's life at baptism, confirmation, marriage, the visitation of the sick and burial.
Cranmer's prose became part of the English language. Till death us do part, earth to earth, ashes to ashes, dust to dust, read them over and the cadence is the point: the book was written to be spoken aloud by congregations, and its collects, short prayers of astonishing compression, remain models of the form. The Prayer Book also fixed the psalter English worship would sing, retaining Coverdale's translation long after other versions superseded it elsewhere, which is why English choral music sets psalms in words otherwise found nowhere else.