Tyrian purple
In 1464, Pope Paul II decreed that cardinals should no longer wear Tyrian purple, and instead wear scarlet, from kermes and alum, since the dye from Byzantium was no longer available. Bishops and archbishops, of a lower status than cardinals, were assigned the color purple, but not the rich Tyrian purple. They wore cloth dyed first with the less expensive indigo blue, then overlaid with red made from kermes dye.