As seen in yesterday's post, the past can teach us great techniques, but can also reintroduce us to the history of certain materials that we take for granted in our times, let's think for example about dyes.
Most of the dyes employed in the modern fashion industry are the results of industrial and synthetic processes and they are therefore the cause of terrible pollution, but in ancient times dyes were derived from natural sources. As highlighted in a display at the Museum of Malacology in Cupra Marittima, Italy, Tyrian purple came for example from the Bolinus brandaris, more simply known as the "purple dye murex" or the "spiny dye-murex".
This edible sea snail characterised by a sculpted shell comes from the family Muricidae, murex snails or rock snails. These snails produce in the mucus of their hypobranchial glands a milky secretion without colour when fresh (used by the mollusc to sedate preys or to defend itself when attacked by predators), that turns into a lasting dye when exposed to the air. In ancient times the mollusc species was used to produce Tyrian purple, a reddish-purple natural dye (one of the dye's main chemical ingredients is dibromo-indigotin).
Sea snails of the species Hexaplex trunculus were also used to produce a purple-blue or indigo dye. These dyes were used by Ancient cultures: the Cretans knew how to make it, while the Phoenicians credited the invention of Tyrian purple to mythological hero Melkart. The Minoans and the Greeks also created dyes from the murex snails.
As you may guess, extracting the dye was a laborious and time-consuming activity that involved tens of thousands of snails (ten to twelve thousand snails of Murex brandaris produced around 1gr of dye, enough to colour only the trim of a single garment...), the dye was therefore highly valued and expensive, but at the same time it was very fashionable since it did not fade easily but became brighter with weathering and sunlight.
The reddish colour of Roman togas like the ones donned by emperors, magistrates or generals derived from Tyrian purple. The toga picta in Tyrian purple and gold was worn by the Roman emperors, and the colour also entered the language - the phrase "donning the purple" meant indeed "becoming emperor" (as the centuries passed the connection continued - in the 9th century the child of an emperor was described as "porphyrogenitos", that is "born in the purple").
Prized by Romans, it became a sign of royal and religious power. It was also popular in Byzantine times as proved by the depictions of Emperor Justinian I and his wife Empress Theodora, clad in Tyrian purple, in the mosaics at the Basilica of San Vitale, Ravenna, Italy (the Byzantine court stopped using Murex purple after the sack of Constantinople in 1204).
One of the most interesting points about the shells was that the results of purple dyeing were never the same as the colour depended on sunlight exposure, on the amount of snail glands used, on the freshness of the molluscs and the species, which meant the purple dye mollusc could provide a wide variety of shades going from reddish to violet and blue.
Yet the dye had its disadvantages: the smell of the molluscs was so bad that it stayed with the dyers and the Talmud granted women the right to divorce an husband who became a dyer after marrying as the smell of his hands would have been extremely disagreeable.
It would be expensive and unnecessary to recreate this dye in our times, but the story of the purple dye is intriguing, in the same way as the structure and texture of the Murex seashell egg casings is fascinating. The female shells add their egg capsules to a communal mass, creating egg masses that can be dozens of times larger than an individual murex snail. These clusters of eggs have a sort of sponge-like structure that is soft to the touch and can be easily squeezed when found in the sea or on the beach. When you dry them they become brittle and fragile and tend to keep on expelling the sand lodged in the egg casings. If you've been careful and wise while washing them, though, they won't be too smelly, and you will be able to keep the casings for study reasons and avoid at the same time to stink like an early murex dyer.