I have been reading about the Middle Ages to remind myself about aspects of this key transitional era in our Western history. One of the delights is to have small illustrations of contemporary illuminated manuscripts by artists such as Loyset Liédet of Bruges, who did many of the illustrations for Jean Froissart's Chronicles in the text prepared for Luis de Gruthuuse, a wealthy Flemish nobleman. In these miniatures, people are the most important part of the image, and the landscape behind is purely secondary and very idealised. For instance, the painting of the Battle of Poitiers 1356, shows an idyllic backdrop of blue mountains and peaceful scenery which contrasts sharply with the battle depicted in the foreground.

The same treatment was meted out to landscapes in medieval wall paintings and tapestries; they were merely the background to human activity. Battles, religious events, societal changes were worth recording. Nature was not of much importance,

This state of affairs continued for many years, with artists paying some attention to landscapes and nature - think of Leonardo da Vinci's studies of dogs, horses, water flowing or landscapes in Tuscany... or Albrecht Dürer's studies of flowers, rabbits, countrysides. But in France, the landscape did not become an independent and valid subject for artists to paint and draw until the 1620s, when it became more of a specialised subject. Claude Lorrain was one of the pioneers in landscape painting, but his works were idealised and romantic to say the least. Interest in landscapes increased gradually until artists such as Jean-Baptiste Corot became a skilled interpreter of the landscape, even if he did do many "pot-boilers" to earn his living. By his time, landscape painting was being taught in the art academies in France, although it was a genre that was ranked pretty low on their "intellectual or moral content" scale. History painting and portraiture were still far more highly esteemed. Landscape painting, which did not require knowledge of anatomy, still had to be idealised really to win respect and admiration from connoisseurs and other artists.

Then came the radical change in France. Pierre Henri de Valenciennes worked hard within the Academy to establish a Prix de Rome for "historical landscapes", advocating that artists paint a "portrait" of a landscape. His publication, Eléments de perspective pratique à l'usage des artistes, (Elements of Practical Perspective for Artists, 1799-1800), was a key influence for artists painting landscapes for decades. By the 1830s, Charles-François Daubigny was painting outdoors in the Fontainbleau region, soon joined by others, like Millet, in the Barbizon School, while another group was forming on the coast near Le Hâvre, led by Eugène Boudin. Monet joined him as a student, and the rest, as they say, is history. Pisarro, Sisley, Renoir, Van Gogh, Cézanne and even Degas on occasions - they all worked outdoors. Edouard Manet tried his hand too at plein air when he painted a small work, "Effect of Snow at Petit-Montrouge", in 1870, when he was on guard during the siege of Paris in the Franco-Prussian War.

These artists had all completely altered the concept and quest for beautiful painted landscapes. No longer was anything idealised. Instead the 19th century French artists, and especially those who became known as the Impressionists, turned their energies and their passion towards portraying the landscape as real, as they saw it, experienced it firsthand and interpreted it. They showed not only nature's beauties but also its intricacies and vagaries. Nature had been transformed and placed centre stage, no longer subservient to any human presence in the work of art. A huge change from the careful, tiny depictions of background idealised landscapes of medieval times....