T J McNamara: Height of rococo elegance

A king's mistress, artistic dictator and the soul of rococo style, Madame de Pompadour is the subject of a fascinating exhibition at the National Gallery in London.

Styles go in and out of fashion. For a long time nobody had a good word to say for the baroque style, and its sweet extension into rococo in the 18th century was completely beyond the pale.

Anything before the cataclysm of the French Revolution was not considered much. The revolution was the culmination of the contrasts of the 18th century: misery for the poor and the utmost elegance, delicacy and exquisiteness for the rich.

The leader and epitome of that serpentine rococo elegance was Madame de Pompadour. In the 19th century she was disapproved of, and in the 20th century derided as the mistress of a stupid king of France, Louis XV, and the provider of young girls for him when her own charms faded.

But interest in rococo has recognised it as a deliciously decorative ensemble style, and Pompadour herself as one of the most influential patrons in history - and one who still influences us.

The exhibition at the National Gallery has been mounted with the Wallace Collection at Hertford House in Manchester Square. The Wallace Collection was needed because it is a great repository of 18th century rococo art and is almost unique in the way the art, particularly of Pompadour's favourite painter, Francois Boucher, is matched with the furniture of the period.

The difficulty was that the trust rules mean nothing can ever leave the Wallace Collection, so the show had to be in two parts.

Madame de Pompadour was born in 1721 to fairly humble parents, although her father in reality may have been the wealthy man who paid for her education.

She was educated in a nunnery and excelled at acting, singing and dancing. Her abilities and beauty enchanted Paris. She married a young man in minor aristocracy and had two children.

Her talents and beauty caught the eye of Louis XV and he ordered a masked ball where the king - disguised as a clipped yew tree - contrived to dance with the beautiful young mother. Soon after, she was installed in the palace at Versailles as an official mistress. The artist, Cochin, made a print of the occasion which you can see in the show.

The king was besotted with her and her lively conversation, and soon she wielded power not only over him but over the economics and politics of the country.

She was passionately devoted to the arts, and encouraged painters, sculptors, decorators, tapestry weavers and manufacturers of porcelain. She sincerely believed that she was encouraging manufacturing and giving craftsmen work.

The exhibition is filled with paintings of the woman herself, and with the style of ceramics, tables, chairs and toiletries she inspired. The king is there too, in a huge painting that shows him in full regalia improbably supervising the Battle of Fontenoy.

The portraits of Pompadour range from pictures of stunning elegance done by Boucher when she was young, to less flattering portrayals of her in middle age with a double chin and a solemn, religious expression.

In the portraits she is surrounded by symbolic objects. There are always books to show her reading and her encouragement of literature, sometimes symbolic statuary to show her charity and, perhaps, a little dog to symbolise devotion.

The most amazing of these portraits is by Boucher, in the Wallace Collection. In this picture she stands in a garden, holding a fan, with her Prince Charles spaniel beside her and a statue of Charity behind.

She is wearing a dress of mind-boggling elegance and intricacy. Below the low neckline are rank on rank of ribbons and bows and on each sleeve are huge billows of lace.

The layers of underskirts are decorated with intricate stitching of floral patterns and rosettes of the utmost elegance which match exactly the roses the painter has put into the foreground, and the flowers she wears on her neckline.

The principal colour of the dress is a delicate apricot. It is impossible to imagine a fashion more graceful.

The other side of the coin, the 18th century contrast, is to consider how many seamstresses must have risked their eyesight to stitch this creation.

Boucher was Pompadour's favourite painter, and her patronage helped him become president of the academy.

His paintings are remarkable for their subtle colour, particularly the delicate combinations of blue and pink, and they are frequently designed to be placed along staircases, over doors or above fireplaces, with their elaborately gilded, twisting frames matching the furniture they inspired.

There are two huge paintings on the staircase in Hertford House that once belonged to Pompadour.

They are filled with totally unconvincing gods and goddesses, nude, pink and dimpled, absurd but with a special kind of charm.

They represent a frivolous world that a generation later was swept away by the revolution.

It was Madame de Pompadour who was credited with the famous remark, "Apres nous le deluge". She died, aged 42, before the flood.