Song of the Sibyl.

The Song of the Sibyl is a liturgical drama Gregorian melody was widely publicized during the Middle Ages (in Southern Europe), which is traditionally interpreted in the mince (Midnight Mass) in Churches Island of Mallorca (Balearic Islands, Spain) and in the city of Alghero (Sardinia, Italy). 

Indeed, Mallorca and Alghero are the only two places in this song is a tradition that extends from the late Middle Ages to today, having been immune to the ban occurred at the Council of Trent (1545-1563). Precisely because of this, on 16 November 2010, this tradition was declared by UNESCO as Intangible Heritage of Humanity.

Sybil is a doomsday prophetess of classical mythology, introduced and adapted to Christianity by analogy can be drawn between this prophecy and the biblical concept of Judgment. 

The oldest evidence of this Christianized song, and sung in monasteries, is contributed by a Latin manuscript of the Monastery of Saint Martial de Limoges (France), in the Carolingian Empire. In Spain, the oldest document preserved a manuscript of the Visigoth period, belonging to the Mozarabic liturgy. From the eleventh century data also Ripoll manuscript written in Latin, in the field of Hispanic liturgy.

The Song of the Sibyl constituted, therefore, a Christian cultural tradition which had as its central theme the Day of Judgement (trial to be broadcast on Good and bad people). Initially it was not like today's Christmas Eve. 

Letter Song of the Sibyl (Mallorca, XV century).

The day of judgment will come to anyone who has served. 

Jesus Christ, Universal King, eternal God and true man, he will come from the sky. And each one just given. 

Sky will drop a big fire: seas, springs and rivers, everything will burn. Fishes show great shouts, losing natural delights. 

Before Judgment, the Antichrist will come, and everyone will torment. He will be served, as God. Who does not want to believe, he will kill him. 

His reign will be very short. At that time, his power, die martyrs, all on one site, and those two saints, Elijah and Enoch.

The Sun will lose clarity, showing dark and clouded. The moon will not give light and the world will be sad. 

The King of the Universe will say to the wicked, very angrily: 

- Go, you cursed, into the torment! Go with the eternal fire! Go to hell with your prince! 

The King of the Universe will say to the good: 

- My children, come! Blessed, inherit the kingdom which I have given you since the world was created!

Oh humble Virgin! You who have given birth to the baby Jesus tonight.Pray to your son to save us from hell! 

The day of judgment will come to anyone who has served.

https://www.youtube.com/watch?v=5BniECJ7GC0