"Alternately, if the dye for a given hue or color came from something rare or foreign or difficult to process (for instance, in all three cases, Tyrian or royal

"Alternately, if the dye for a given hue or color came from something rare or foreign or difficult to process (for instance, in all three cases, Tyrian or royal purple, which came from the murex sea snails – if you have ever wondered why no country has purple as a national color this is why, before synthetic dyes, coloring your flags and uniforms purple would have been bonkers expensive), then it was going to be expensive and rare and there just wasn’t much you could do about that." The wearing of Tyrian purple clothes (made from the murex snails) was just banned for commoners in Rome, and its production was seriously disrupted if not stopped after the fall of Constantinople, to the extent that soon after that Roman Catholic Cardinals were commanded to wear red instead of purple garments, which they had formerly been treated to. This extraordinarily profitable business in dye is why Byzantium is so often coloured purple in video games like Civilization.