It is pretty much common knowledge that throughout much of human history, the color purple was worn by royalty, high priests, and other very important people. It got this reputation because purple is not an easy color to make and isn’t found often in nature, or at least not in a way that can be used to make dye.

Even after it was found that one of the most effective purple dyes used in ancient history was taken from a gland in a particular sea slug, experts didn’t really know how they were able to make enough of it to meet the demand of the rich and famous of the day.

According to a study that was published in the journal PLOS ONE, however, it seems that this question has finally been answered.

There appears to have been a large-scale purple dye ‘factory’ located near modern-day Haifa, Israel. This facility churned out large vats of this pigment and very likely dyed cloth onsite as well. What is perhaps even more impressive is that, based on the number of dyed objects in the area, it looks like this location was used for around 500 years.

Golan Shalvi is the study’s author and answered some questions via email to IFLScience about this remarkable find. She said:

“[Purple dye] is made from a gland found in the marine mollusk Hexaplex trunculus. Finding large quantities of these mollusks, extracting the glands with precision, and preparing the dye through complex redox chemical processes required tremendous effort and skill. As a result, only the elite could afford it, and it became a symbol of wealth, power, and sanctity – used by rulers, high priests, and for temple worship.”

The color is known as Tyrian purple and was most often used on woolen textiles. On the archaeological location cited in this study, there were dye-stained vats that were large enough to hold as much as 350 liters of the dye.

It stands to reason that this large facility also raised the snails onsite or else had reliable access to them in the waters nearby. Either way, being able to make such a large amount of dye required access to huge numbers of the snails.

The study also says that the dye was made indoors, which means the snails were harvested inside. The smell of these animals was likely repulsive, but this would have been necessary to create a reliable coloring of the dye.

This location, called Tel Shiqmona, looks to have been in operation from around 1100 to 600 BCE. It is likely that production of the purple dye only stopped because the area was overrun by the Babylonian army.

This site is very helpful in learning more about the dye, how it was made, and how it was used in the region. Shaliv commented:

“The purple dye production site at Tel Shiqmona is exceptional in the broader archaeological record. It contains more ancient purple-dye stained finds than all other known sites around the Mediterranean combined.”

This new knowledge will help other researchers piece together how these ancient people lived, especially those with enough wealth to afford beautiful purple garments.

If you thought that was interesting, you might like to read about 50 amazing finds on Google Earth.