very popular medium into the 20th century, but was often classed as a lower form of art than an imagined landscape. Landscapes in watercolour on paper became a distinct specialism, above all in England, where a particular tradition of talented artists who only, or almost entirely, painted landscape watercolours developed, as it did not in other countries. These were very often real views, though sometimes the compositions were adjusted for artistic effect. The paintings sold relatively cheaply, but were far quicker to produce. These professionals could augment their income by training the "armies of amateurs" who also painted. Leading artists included John Robert Cozens, Francis Towne, Thomas Girtin, Michael Angelo Rooker, William Pars, Thomas Hearne, and John Warwick Smith, all in the late 18th century, and John Glover, Joseph Mallord William Turner, John Varley, John Sell Cotman, Anthony Copley Fielding, Samuel Palmer in the early 19th. 19th and 20th centuries The Romantic movement intensified the existing interest in landscape art, and remote and wild landscapes, which had been one recurring element in earlier landscape art, now became more prominent. The German Caspar David Friedrich had a distinctive style, influenced by his Danish training, where a distinct national style, drawing on the Dutch 17th-century example, had developed. To this he added a quasi-mystical Romanticism. French painters were slower to develop landscape painting, but from about the 1830s Jean-Baptiste-Camille Corot and other painters in the Barbizon School established a French landscape tradition that would become the most influential in Europe for a century, with the Impressionists and Post-Impressionists for the first time making landscape painting the main source of general stylistic innovation across all types of painting. The nationalism of the new United Provinces had been a factor in the popularity of Dutch 17th-century landscape painting and in the 19th century, as other nations attempted to develop distinctive national schools of painting, the attempt to express the special nature of the landscape of the homeland became a general tendency. In Russia, as in America, the gigantic size of paintings was itself a nationalist statement. In Poland the main representatives of landscape painting, in the 2-nd part of XIX century, were Maksymilian Gierymski, Józef Chełmoński and Stanisław Masłowski In Spain, the main promoter of the genre was the Belgium-born painter Carlos de Haes, one of the most active landscape professors at the Academy of Fine Arts of San Fernando in Madrid since 1857.