national color of Italy (from the livery color of the former reigning family, the House of Savoy). King Louis IX of France, better known as Saint Louis (1214–1270), became the first king of France to regularly dress in blue. This was copied by other nobles. Paintings of the mythical King Arthur began to show him dressed in blue. The coat of arms of the kings of France became an azure or light blue shield, sprinkled with golden fleur-de-lis or lilies. Blue had come from obscurity to become the royal color. Light blue is often reported as the color of the visible light coming off of a source when ionizing radiation is released during a nuclear chain reaction. The signature "light blue glow" of Cherenkov radiation seen in nuclear reactors is a result of the constant particles and photons being ejected out of the reactor core into the water medium around it. In boxing, light blue is the official tone of a World Boxing Association referee's dress shirt. References