This is a Basque Christmas folk carol about the revelation to Mary, the mother of Jesus, by the angel Gabriel that she would conceive a child to be born the Son of God. The song, which dates back to the 14th century, quotes the biblical account of that event and Mary's Magnificat both from chapter 1 of the Gospel of Luke.
Sting recorded this for his 2009 album, If on a Winter's Night. He explained to Mojo magazine January 2010 why he recorded a song about The Nativity despite being an agnostic. Said Sting: "I enjoy reading Richard Dawkins and Christopher Hitchens and I think they're funny, but attacking the fundamentalist idea of what God is like is as easy as hitting a bull elephant with a shotgun. What I believe in is the human imagination. Religion is a product of that just like literature or music, so to deny religion is to deny part of what it means to be human. I don't believe for a second that Mary had a baby and stayed a virgin. But it's a magical story and it has power."
The TV show Cheers was nearly canceled after its first season, but the theme song, "Where Everybody Knows Your Name," was very popular. To satisfy viewer demand, the theme was made into a full song and released as a single.