Born on a cold night in the chapel of a small Austrian village, "Silent Night," the most famous Christmas carol in the world, celebrates this year its 190th anniversary.
The song, known as "Stille Nacht" in the original German, was first performed on December 24, 1818, in the tiny hamlet of Oberndorf, as a local assistant priest, Joseph Mohr, sought to comfort his flock, racked by poverty and misery in the aftermath of the Napoleonic Wars.
"He asked his friend Franz Xaver Gruber, a teacher, to compose the music for six verses he had written two years prior, and they performed the song together at mass with the help of a simple guitar," says Renate Ebeling-Winkler, a historian and expert on the topic.
The song was an immediate success but remained a close-kept secret for many years, until an organ delivery-man from Tyrol took note of it on his way through the village.
It soon became a favourite with Tyrolean singers, travelling up and down the continent in the winter to earn money.
"Admired for its resistance to Napoleon, Tyrol was very popular with allied countries and its best singers, like the Rainer family, were world stars," notes Ebeling-Winkler.
These artists gave "Silent Night" - which became known as a "popular Tyrolean song" - worldwide fame, performing it at the royal court in London in 1827, in Moscow in 1831 and in New York in 1839.
By this time, its origins had been largely forgotten and Mohr died in 1848 without ever knowing of his song's success.
Franz Xaver Gruber only found out about it in 1854 when the carol was almost attributed to Michael Haydn, the brother of famed composer Joseph Haydn.
But "Silent Night" had already made its way into German school books and into the Catholic and Protestant churches, which spread it further still with the help of their missionaries.
Often seen as the quintessential Christmas carol, it has been translated into over 330 languages, bridging social, religious and cultural divides and contributing to a brief moment of truce in the trenches of World War I on Christmas Eve 1914.
"It's simply a beautiful song, wonderfully simple and which, like Mozart, speaks to everyone and goes far beyond religion," says Oberndorf's current parish priest Nikolaus Erber.
Every year, thousands of tourists, many from Asia, travel to the little village to take part in a Christmas Eve ceremony in front of the small chapel that has now replaced the original "Silent Night" church.
"Oberndorf is like the Bethlehem of the song," says Erber with a smile.
This year again, some 10,000 visitors are expected on December 24.
And the enthusiasm is such that replicas of the Oberndorf chapel have been built as far as the US state of Michigan, while a new compilation of songs features a hard rock cover of "Silent Night."
Not that nights have always been silent in Oberndorf.
"In 1818, midnight mass was banned because the authorities had noticed that people were often drunk and disorderly," notes Ebeling-Winkler.
This year, 190 years after the first performance, the "Silent Night" ceremony will again be held in the afternoon... and broadcast live on the Internet.