Eugène Delacroix, France’s leading romantic painter of the first half of the 19th century, advocated the opposite aesthetic of his contemporary, Jean–Auguste–Dominique Ingres. In contrast to Ingres' controlled images that are characterized by his interests in linear purity and a finished surface, Delacroix championed the primacy of color and quick execution as expressive of the artist's imagination.
The Arabs Skirmishing in the Mountains was painted a few months before the artist's death. It harks back to Delacroix’s first and only visit to North Africa in 1832, more than 30 years before this picture was painted, an excursion that made a deep impression on him. The figures and horses are placed on a diagonal that traverses the lower right foreground plane. The action then shifts to the middle ground as a horse and rider charge towards battling Arabs in the center. The background abruptly rises into a craggy landscape, with a fortified castle and a line of mountains blending with the clouds.
The fluidity of Delacroix's brushstroke animates the composition, heightening the violence of the scene and the moment when the rider is thrown off his horse. The brilliant use of red, blue, and white forces the eye to stop at each grouping, accenting the rhythm of the battle itself. Delacroix has created a fictive battle, his work not only recalling an earlier personal experience but also stimulating the imagination of his viewers.
More information on this painting can be found in the Gallery publication French Paintings of the Nineteenth Century, Part I: Before Impressionism, which is available as a free PDF https://www.nga.gov/content/dam/ngaweb/research/publications/pdfs/french-paintings-nineteenth-century.pdf