Messiah

One of the most famous and beloved pieces of music ever written is Handel's Messiah.  It is normally played at Christmastime (although it premiered on Easter), and is most recognizable through the Hallelujah Chorus.  While George Frederic Handel was considered a successful German composer and one of the most notable composers of the Baroque time period, the writing of Messiah still seems to be kind of an unlikely story.  Born in Germany in 1685, Handel first moved to Italy in attempt to compose opera.  This was largely a failure, however, so Handel moved back to Germany and then eventually to England, where he would write and perform for King George himself.  However, this relationship was often up and down, and Handel eventually fell out of favor.  In 1737, he apparently had a debilitating stroke that both caused blurry vision and paralyzed his right arm, making it impossible for him to play or conduct.  On top of this, he was not the best businessman; this left him rather deep in debt.  It was in this situation and state of mind that Handel came across a liberetto by Charles Jennens, which was divided into three parts and dealt with all aspects of the story of Jesus Christ, the Messiah.  This story would provide the inspiration that would lead to Handel's unlikely composition of a Christian oratorio- this oratorio would become one of the most celebrated Christian musical pieces of all time: Messiah.  In fact, while writing the most well known part of this composition, the Hallelujah Chorus, Handel claimed that "I did think I saw heaven open, and saw the very face of God."
http://blog.beliefnet.com/bibleandculture/2009/12/handels-messiah----the-story-behind-the-classic.html

Here's a link to see the Mormon Tabernacle Choir singing the Hallelujah Chorus:
http://youtu.be/S4BWhvIlFVE