THE Pope is coming to Britain.Various local observers will have different reactions to this event.
In my household, however, there will be joyous cheering and whooping.
Not for religious reasons, mind you.
I'll be cheering because Benedict XVI's visit has enabled something monumental to occur in the world of art and culture.
To mark the papal visit, the Vatican is lending to London's Victoria and Albert Museum, for the first time, four of the tapestries Raphael imagined for the Sistine Chapel. These are going to be shown alongside the full-size designs he made for them, the so-called Raphael Cartoons.
This is a true miracle. The Vatican - possibly the least willing, least adaptable, least approachable, least helpful, least persuadable and most arrogant institution on earth - is lending some of its most precious cargo to the descendants of Henry VIII.
Regular visitors to the Victoria and Albert will be aware of the significance of the Raphael Cartoons. They have been hanging in the museum since 1865 and are rightly considered to be among the most important surviving masterworks of the Renaissance.
When Leo X, the Medici pope, ascended to the holy throne in 1513, he was determined to leave his own mark on the papacy.
There was, however, a problem.
The Sistine Chapel was already painted. Botticelli, Ghirlandaio and Perugino had long since added a thick layer of masterpieces all the way round the walls, and Michelangelo had now nabbed the remaining space.
What, though, if a temporary solution could be found? A way of bringing great art into the chapel in such a manner that it could be taken out again?
If Michelangelo's young rival, Raphael, were to design a set of tapestries for the lower levels of the Sistine Chapel, which would only be displayed on the most important papal occasions, would they not appear even more special?
Tapestries were the most precious art form of the day. In our world, they are outrageously underappreciated. But in Raphael's time, they were mind-bogglingly expensive.
A fine painting might take a man a month to paint, but a fine tapestry would take 10 men a year to weave.
They were made of such precious stuffs, too. Look carefully at the Raphael creations Pope Benedict is sending and you will see gold threads and silken knots; fiendishly complicated perspectival effects and incredibly skilful woven illusionism.
When Leo X chose to make his contribution in tapestries, he was upping the ante.
The rivalry between Michelangelo and Raphael is one of the defining anecdotal competitions of the Renaissance: Michelangelo was old, angry and homosexual; Raphael was young, handsome and charming.
Finding themselves in the Vatican together, these two geniuses on opposite ends of the experience scale embarked upon a game of aesthetic one-upmanship that resulted in some of the era's greatest art.
Technically, Raphael's weavings constitute an addition to the existing decor of the Sistine Chapel; emotionally, they attempt an audacious conquest of the lower levels. I speak on this with some authority because I have seen them in the Sistine Chapel.
They usually hang in their own gallery at the Vatican; the last time they returned to the Sistine Chapel was for a single day in 1982.
Before that, nobody is certain if they were briefly on show in the last century or the one before.
A month ago, however, a call came from the Victoria and Albert. Would I like to go to Rome to see the tapestries hanging in the Sistine Chapel? Would I what? I was soon jetting it to Rome to witness one of the rarest sights in art.
It turns out that Benedict XVI, to his eternal saintly credit, is an art lover. He knows about Raphael, he knows about the tapestries, he knows about the cartoons, and he imagined it would be a welcome gesture from a visiting pontiff to engineer a British reunion of the two.
When Leo X's demented predecessor, Julius II, rebuilt the chapel and brought in Michelangelo to paint the vault, he left a ring of painted curtains covered with his family's coat of arms all the way round the chapel's lower walls, where you could not miss them.
Inevitably, your eyes swivel quickly upwards towards Michelangelo's astonishing ceiling.
But when I strode into the Sistine Chapel this time, I was confronted, instead, by a whole new ring of stories; an entire new stratum of meaning; a fresh level of iconographic action.
Magnificently full already with so many superior religious sights, the chapel now had Raphael tapestries as well, where the painted curtains used to be.
Back in London, the reason why the paper cartoons for the tapestries are in such fine condition is because they were not, originally, seen as artworks in themselves.
Their function was to supply Flemish weavers with practical designs. To make this easier, they were cut into handy strips and stored in boxes. Only centuries later, when they were stuck back together and shown as a whole, could we actually see how fine they were.
The Victoria and Albert has seven of the cartoons, which are being compared in London with four of the tapestries.
One set of images faces to the right and the other to the left. This is because the tapestries had to be mirror images of the cartoons.
Three of the tapestries come from the series tracing the story of St Peter, the first bishop of Rome and, therefore, the first pope.
Christ's Charge to Peter shows Jesus handing his first disciple a huge key: the key to the kingdom of heaven.
In the Miraculous Draught of Fishes, probably the first design Raphael drew, Peter is seen on his knees on a boat, thanking the seated Jesus for filling his nets with fish. To which Christ replies: "I will make you a fisher of men."
SIC: TA/AUS