Violet is the color of light at the short wavelength end of the visible spectrum, between blue and the invisible ultraviolet. It is one of the seven colors identified by Isaac Newton in 1672 by dividing the spectrum of visible light. Violet light has a wavelength between 380 and 435 nanometers. The color name comes from the purple flower. In the RGB color model used on computers and television screens, purple is created by mixing red and blue light with more blue than red. In the RYB color model historically used by painters, purple is created from a combination of red and blue pigments and sits on the color wheel between blue and purple. In the CMYK color model used in printing, purple is created by a combination of magenta and cyan pigments, with more magenta than cyan. Purple is closely related to violet. In optics, violet is a spectral color (referring to the color of different wavelengths of light), while violet is the color of various combinations of red and blue (or violet) light, some of which humans perceive as similar to purple. In common usage, the two terms are used to refer to a variety of colors between blue and red. Purple has a long history of association with royalty, originally because Tyrian purple dye was extremely expensive in ancient times. The emperors of Rome wore purple togas, just like the Byzantine emperors. In the Middle Ages purple was worn by bishops and university professors, and was often used in art as the color of the Virgin Mary’s robes. In Chinese painting, the color purple represents “the unity that transcends the duality of yin and yang” and “the ultimate harmony of the universe”. In Hinduism and Buddhism, purple and/or violet are associated with the crown chakra. A European study suggests that purple is the color most commonly associated with extravagance, individualism, vanity and ambiguity.