In which century did color theory begin to be systematically studied?
The 19th century also saw the use of red in art to create specific emotions, not just to imitate nature. It saw the systematic study of color theory, and particularly the study of how complementary colors such as red and green reinforced each other when they were placed next to each other. These studies were avidly followed by artists such as Vincent van Gogh. Describing his painting, The Night Cafe, to his brother Theo in 1888, Van Gogh wrote: "I sought to express with red and green the terrible human passions. The hall is blood red and pale yellow, with a green billiard table in the center, and four lamps of lemon yellow, with rays of orange and green. Everywhere it is a battle and antithesis of the most different reds and greens."
Music was an important part of both secular and spiritual culture, and in the universities it made up part of the quadrivium of the liberal arts. From the early 13th century, the dominant sacred musical form had been the motet; a composition with text in several parts. From the 1330s and onwards, emerged the polyphonic style, which was a more complex fusion of independent voices. Polyphony had been common in the secular music of the Provençal troubadours. Many of these had fallen victim to the 13th-century Albigensian Crusade, but their influence reached the papal court at Avignon.