The traditional Nativity Scene built each Christmas in front of St Peter's basilica in Rome will this year show Jesus being born not in a stable but in Joseph's house.
In a move which is unprecedented in modern times, the Vatican has decided to abandon the traditional manger and straw-laden setting in order to reflect the more straightforward scenario described by St Matthew.
So Vatican workmen are now busy putting up a three-part Nativity Scene centred on a room in Joseph's house where Mary will be shown with her newborn baby.
On the left there will be Joseph's workshop and on the right, symbolising the presence of bustling material values alongside spiritual ones, there will be a busy inn.
Discussing the new departure at a press conference on Thursday, Vatican officials said the backdrop for the scene - which is always built to life-size proportions - would aim to reflect a Palestinian landscape.
In another break with tradition, there will be some new statues. Four angels sent from Mexico will stand around Mary and a number of new wooden figures sent by the north Italian province of Trento will complete the scene.
The statues representing Mary, Joseph, the baby Jesus and the wise men will be the same ones used every year. Some of them date back to a Nativity Scene created for Pope Gregory XVI in 1842.
The nativity scene, or crib, has been a regular Christmas fixture in St Peter's since 1982, when the custom of building a four-metre-high house with lifesize figures in it was resurrected by John Paul II.
Along with the giant fir tree which is always placed near it in the square, the crib has become a trademark of Roman Christmases and families often make special trips to see it.
Elaborately decorated cribs, sometimes containing dozens of figures of people and animals, are a standard Christmas feature in millions of Italian households.
The Vatican gave no indication of why a different approach had been taken with the Nativity Scene this year. Some observers suggested it was perhaps an attempt to highlight the differences in the Bible accounts of Jesus's birth.
Unlike the Bible's most famous versions of the event, written by St John, St Mark and St Luke, the one written by St Matthew makes no mention of an improvised birth in a cave or stable with attendant shepherds.
The implication in the scanty narrative is that the baby was born in the house of his carpenter father.
It reads as follows: ''When Joseph woke up, he did what the angel of the Lord had commanded him and took Mary home as his wife. But he had no union with her until she gave birth to a son. And he gave him the name Jesus''.
