“For many years, the hills of southern France were home to shepherds whose duties required their presence day and night, year-round. To celebrate the birth of Jesus, a custom evolved among the shepherds that can’t be traced to an exact date. On Christmas Eve, these shepherds shouted ‘Gloria in excelsis Deo, Gloria in excelsis Deo!’ from hill to hill, spreading the celebratory news.
There is speculation that this spirited chant originated in a medieval Latin chorale. Eighteenth-century music later fused words with melody to become the French carol ‘Les Anges dans nos Campagnes.’ The version we sing today was first published in a collection of holiday carols in 1855.”
Source: TLC’s website