The episode is part of a daily Advent calendar series that offers historical facts instead of chocolates. It focuses on the color blue, noting it has been the most popular color in the West since 1890. Blue is used by organizations like the EU, NATO, UNESCO, and the UN for their flags. In antiquity, blue did not officially exist, with only white, red, and black recognized as colors. Greeks could see blue in nature, but it was associated with barbarians and considered disreputable, especially for women with blue eyes. The term 'blue' derives from Germanic and Arabic roots, not Greek or Latin. Blue was difficult to produce and maintain, with only ancient Egypt having a stable copper-based recipe that was lost. Between the 12th and 13th centuries, the Catholic Church revolutionized blue's perception by linking it to divine light. This led to blue being used in church art, such as painting skies blue and adopting it as the Marian color. The color system expanded to include blue, green, and yellow alongside white, red, and black. Church figures like Abbot Suger promoted color in worship spaces, benefiting blue. French kings, starting with Philip Augustus and Saint Louis, adopted blue, making it fashionable among nobility. Demand for woad, the plant used to make blue dye, surged, enriching regions like Picardy and Toulouse. The Protestant Reformation later favored blue in men's fashion alongside gray and black. The Romantic movement embraced blue for its melancholic associations. From the 18th century, blue became the dominant color in Europe due to new techniques. A Berlin pharmacist invented Prussian blue, and indigo was imported from the Caribbean and Central America. Levi Strauss's creation of jeans in 1850 solidified blue's place in Western society, including its use in workwear for laborers. Blue's popularity has made it a consensual, almost conservative color, uniting diverse groups under common symbols. However, its ubiquity has made it nearly invisible, echoing its ancient obscurity.
