"Picardy" is a hymn tune used in Christian churches, based on a French carol; it is in a minor key and its meter is 8.7.8.7.8.7. Its name comes from the province of France from where it is thought to originate. The tune dates back at least to the 17th century, and was originally used for the folk song "Jesus Christ s'habille en pauvre". First published in the 1848 collection Chansons popularies des provences de France, "Picardy" was most famously arranged by Ralph Vaughan Williams in 1906 for the hymn "Let All Mortal Flesh Keep Silence", in The English Hymnal, the words of which are taken from the Byzantine Greek Liturgy of St. James translated by Gerard Moultrie a third master and chaplain at Shrewsbury School.
In addition, Gustav Holst used the hymn in his "3 Festival Choruses" Op. 36a.