On the night before Christmas in 1818, an Austrian clergyman and a music teacher sang a song that they wrote together for the first time. They did not know it then, but their song would go on to be the world’s most famous Christmas carol. The song is called, in English, “Silent Night.” Joseph Mohr, a young clergyman from Salzburg, first wrote the words for a poem in 1816. Two years later, Mohr asked Franz Xaver Gruber, his friend and a teacher from Upper Austria, to write music for the words. Gruber simply added some musical notes to the poem. He did not attach much importance to the piece. On December 24 of that year, Mohr and Gruber sang the song for the first time at the St. Nikola Church in Obendorf, outside of Salzburg. The church’s organ was not working. So, they played the music with a guitar-like instrument. A new hit song was born.