Tyrian purple
Because it was extremely difficult to make, Tyrian purple was expensive: the 4th century BCE historian Theopompus reported, "Purple for dyes fetched its weight in silver at Colophon" in Asia Minor. The expense meant that purple-dyed textiles became status symbols, whose use was restricted by sumptuary laws. The most senior Roman magistrates wore a "toga praetexta", a white toga edged with a stripe of Tyrian purple. The even more sumptuous "toga picta", solid Tyrian purple with a gold stripe, was worn by generals celebrating a Roman triumph.