 The "Book of Common Order", introduced in the Church of Scotland by reformer John Knox in 1564, contained metrical versions of all the Psalms, adapted from John Calvin's "Genevan Psalter" (1539).Psalms were sung to Genevan tunes and were only permitted to be sung in unison.Many revisions were published, but by the mid-17th century, the Churches of England and Scotland were both in need of a new translation.