KEY POINTS:
Two of the loveliest paintings in the Louvre have visited Vienna. The occasion was an exhibition of more than 50 glorious masterpieces of Venetian painting that went first to Washington and then to the Kunsthistorisches Museum in Vienna.
Venetian painting of the Renaissance is so opulently attractive that there have been blockbusting exhibitions of it, notably London's National Gallery exhibition devoted to Titian.
What is special about this show is that it illustrates the beginnings of the greatness of Venetian painting between about 1500 to 1550. It illuminates the wonderful developments in luminous effects that the change from tempera to oils brought to work in Venice and then the world.
It also shows a change in emphasis from religious work, which had dominated, to secular subjects, especially the development of a poetic, pastoral mode based largely on exquisite landscape backgrounds.
As well as offering the sheer visual delight of masterpiece after masterpiece, the exhibition provided an opportunity to make interesting comparisons.
One of the greatest of Venetian painters was the short-lived genius Giorgione. His special contribution was the soft lovely landscapes that were the background to his paintings.
One of his most subtle paintings was an unusual image of the conventional subject of the Adoration of the Shepherds. The colours of the rough jerkins of the shepherds who come to adore the Christ Child are beautifully modulated.
The whole group of adoring shepherds breaks with tradition by being shifted out of the centre of the painting. Jesus with Mary and Joseph and some little angels are in front of the darkness of a cave. This leaves room for a rich landscape that reaches into the distance. Its grace reinforces the charm of the work.
There is a completed version of the work from the National Gallery of Washington but the Kunsthistorisches also has a slightly incomplete version of the same painting.
The big question is: Were they both by the master, or was one a studio copy by a lesser assistant? A side-by-side comparison makes a convincing case that they were both by the great artist, who made slight differences in each version. The incomplete painting is not just a copy by a studio assistant.
The whole question of attribution, who actually did the painting, swirls around one of those splendid paintings on loan from the Louvre.
Perhaps the single most famous Venetian painting is the Concert Champetre. This singularly beautiful work is a pastoral beyond compare and has influenced many painters, notably Edward Manet. He did his own revolutionary variant of it centuries later - at the beginning of the Impressionist movement - as Dejeuner sur l'herbe. It shows two men and two women. The men are clothed. The women are opulent Venetian nudes - they would never get a modelling job today.
One man is dressed as a nobleman and the other is simply dressed. One plays the lute, the other sings. The woman seated by them is holding a recorder. The other woman pours water back into a well. The men appear to take no notice of the women. There is a theory they are the Muses who inspire music and are invisible to the men.
In the background a shepherd guards his flock of sheep. The painting suggests more than two couples on an outing. The whole atmosphere is of a pastoral poem from antiquity or the Renaissance, but no one can agree on which poem.
It is the atmosphere of the work that is magical. Not only is the subject enigmatic, so too is the question of who painted it. For many years the label in the Louvre said it was by Giorgione, perhaps because he was known to love music and women. But Giorgione died young and for many years his friend Titian painted in his manner.
They were both pupils of Giovanni Bellini, the most famous of a family of Venetian painters. Titian became the greatest and most long-lived. Some say he was 99 when the plague killed him.
The greatest of paintings must have been done by the best painter so the painting must be by Titian. Then scholars thought it was perhaps done in part by Giorgione and partly by Titian. Nowadays, when it is home in Paris, it is given entirely to Titian. The question is complicated by its dull surface. The painting would be less mysterious if it were cleaned.
The other wonderful loan from the Louvre is unquestionably by Titian - the superb Portrait of a Young Man with a Glove.
This brilliant image is the typical multi-talented Renaissance figure - courtier, swordsman, scholar, wit, "the glass of fashion and the mould of form".
He is elegant, relaxed and graceful, creating a new ideal that is with us to this day. His image set the pattern for aristocratic portraiture for centuries to come. He is the presiding prince of this incomparable exhibition.
