The "Coventry Carol" is an old English Christmas song from the 16th century. It used to be performed in Coventry, England, as part of a play called "The Pageant of the Shearmen and Tailors," which told the Christmas story from the Gospel of Matthew.
The carol itself talks about the Massacre of the Innocents, where King Herod ordered the killing of all male infants under two years old in Bethlehem. It takes the form of a lullaby sung by mothers of the doomed children.
The music has something called a Picardy third, which is a well-known musical feature. The author is unknown, but the oldest known written version was done by Robert Croo in 1534, and the oldest known musical setting is from 1591. There are also newer versions of the carol by different composers like Kenneth Leighton, Philip Stopford, and Michael McGlynn.
The carol is part of a play called "The Pageant of the Shearmen and Tailors," which is one of the Coventry Mystery Plays performed by the city's guilds. The exact date of the text is uncertain, but there are references to the Coventry guild pageants from 1392 onwards. The surviving text of the carol and the play was edited by Robert Croo in 1534.
In the play, the carol is sung by three women of Bethlehem who come on stage with their children right after Joseph is told by an angel to take his family to Egypt. The lyrics go like this:
"Lully, lulla, thow littell tine child, By by, lully, lullay thow littell tyne child, By by, lully, lullay!"
And so on. It talks about the sadness of the mothers for their children, and how King Herod ordered the killing of young children.
The music for the carol was added later by Thomas Mawdyke in 1591. The carol's music is written in three-part harmony, but it's unclear if Mawdyke composed it or not. The surviving pageants were revived in the Cathedral from 1951 onwards. The "Coventry Carol" gained more popularity when it was featured in a BBC broadcast in 1940 after the bombing of Coventry during World War II.