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BM to expose Tyrian purple – value > gold –

Zaria Gorvett, Tyrian purple: The lost ancient pigment that was more valuable than gold, BBC, 25 November 2023

For millennia, Tyrian purple was the most valuable colour on the planet. Then the recipe to make it was lost. By piecing together ancient clues, could one man bring it back?

(Image credit: Alamy).
At first, they just looked like stains. It was 2002 at the site of Qatna – a ruined palace at the edge of the Syrian desert, on the shores of a long-vanished lake. Over three millennia after it was abandoned, a team of archaeologists had been granted permission to investigate – and they were on the hunt for the royal tomb.After navigating through large hallways and narrow corridors, down crumbling steps, they came across a deep shaft. On one side were two identical statues guarding a sealed door: they had found it. Inside was a hoard of ancient wonders – 2,000 objects, including jewellery and a large golden hand. But there were also some intriguing dark patches on the ground. They sent a sample for testing – eventually separating out a vivid purple layer from the dust and muck.

The researchers had uncovered one of the most legendary commodities in the ancient world. This precious product forged empires, felled kings, and cemented the power of generations of global rulers. The Egyptian Queen Cleopatra was so obsessed with it, she even used it for the sails of her boat, while some Roman emperors decreed that anyone caught wearing it – other than them – would be sentenced to death.

That invention was Tyrian purple, otherwise known as shellfish purple. But though this noble pigment was the most expensive product in antiquity – worth more than three times its weight in gold, according to a Roman edict issued in 301 AD – no one living today knows how to make it. By the 15th Century, the elaborate recipes to extract and process the dye had been lost.

But why did this alluring colour disappear? And can it be resurrected?

In a small garden hut in north-eastern Tunisia, just a short distance from what was once the Phoenician city of Carthage, one man has spent most of the last 16 years smashing up sea snails – attempting to coax their entrails into something resembling Tyrian purple.

After more than three thousand years of mingling with sediment, the Tyrian purple found in Qatna’s royal tomb was still intensely colourful (Credit: Alamy).

A fishy empire

Tyrian purple was paraded by the most privileged in society for millennia – a symbol of strength, sovereignty and money. Ancient authors are particular about the precise hue that was worthy of the name: a deep reddish-purple, like that of coagulated blood, tinged with black. Pliny the Elder described it as having a “shining appearance when held up to the light”.

With its uniquely intense colour and resistance to fading, Tyrian purple was adored by ancient civilisations across Southern Europe, North Africa, and Western Asia. It was so central to the success of the Phoenicians it was named after their city-state Tyre, and they became known as the “purple people”. The shade could be found on everything from cloaks to sails, paintings, furniture, plaster, wall paintings, jewellery and even burial shrouds.

In 40 AD, the king of Mauretania was killed in a surprise assassination in Rome, ordered by the emperor. Despite being a friend to the Romans, the unfortunate royal had caused grave offence when he strode into an amphitheatre to watch a gladiatorial match… wearing a purple robe. The jealous, insatiable lust that the colour ignited was sometimes compared to a kind of madness.

A slimy mystery

Tyrian purple has been found in paintings dating back to the Bronze Age (Credit: Alamy).

Oddly, the most celebrated pigment the world has known did not start life as a beautiful ultramarine gemstone, like its contemporary lapis lazuli – or a vibrant tangle of coral-pink roots, like the red dye madder. Instead, it began as a clear fluid produced by sea snails in the Murex family. More specifically, it was mucous.

Tyrian purple could be produced from the secretions of three species of sea snail, each of which made a different colour: Hexaplex trunculus (bluish purple), Bolinus brandaris (reddish purple), and Stramonita haemastoma (red).

Once snails had been collected, either by hand along rocky coastlines or with traps baited with other snails – Murex sea snails are predators – it was time to harvest the slime. In some places, the mucous gland was sliced it out using a specialised knife. One Roman author explained how the snail’s gore would then ooze out of its wounds, “flowing out like tears”, before being collected into mortars for grinding. Alternatively, smaller species could be crushed whole.

But this is the end of the certainty. Accounts of how colourless snail slime was transformed into the dye of legends are vague, contradictory and sometimes obviously mistaken – Aristotle said the mucous glands came from the throat of a “purple fish“. To complicate matters further, the dyeing industry was highly secretive – each manufacturer had their own recipe, and these complex, multi-step formulas were closely guarded.

“The problem is that people did not write down the important tricks,” says Maria Melo, a professor of conservation science at NOVA University of Lisbon, Portugal.

Murex snails may also have been the historic source of “tekhelet” – a sacred colour in the Jewish tradition mentioned in the Hebrew Bible (Credit: Mohammed Ghassen Nouira).

The most detailed record comes from Pliny, who explained the process in the 1st Century AD. It went something like this: after isolating the mucous glands, they were salted and left to ferment for three days. Next came the cooking, which was done in tin or possibly lead pots on a “moderate” heat. This continued until the whole mixture had been boiled down to a fraction of its original volume. On the tenth day, the dye was tested by dipping in some fabric – if it emerged stained with the desired shade, it was ready.

Given that each snail only contained the tiniest amount of mucous, it could take some 10,000 to make just a single gram of dye. Mounds of billions of discarded sea snail shells have been reported in areas where it was once manufactured. In fact, the production of Tyrian purple has been described as the first chemical industry – and this not only applies to the scale of the operations, but their exacting nature.

“It is not really easy to obtain the colour,” says Ioannis Karapanagiotis, a professor of conservation chemistry at Aristotle University of Thessaloniki, Greece. He explains that Tyrian purple is totally unlike other dyes, where the raw material – such as leaves – contains the pigment already. Instead, the sea snail mucous contains chemicals which can be turned into a dye, but only under the right conditions. “It is quite amazing,” he says. And yet, many crucial details of the process are long forgotten.

In ancient and medieval times, Tyrian purple was so valuable, it was often faked – usually with a combination of blue dye from indigo plants and red madder (Credit: Alamy).

An abrupt decline

In the early hours of 29 May 1453, the Byzantine city of Constantinople was captured by the Ottomans. This was the end of the Eastern Roman Empire – and it took Tyrian purple with it.

At the time, the city’s dyeworks were at the centre of the industry. The colour had become deeply bound to Catholicism – worn by cardinals and used to dye the pages of religious manuscripts. But it had already been suffering, after a succession of excessive taxes. Now the church had lost control of the pigment’s production altogether. So, the pope soon decided that red would become the new symbol of Christian power. This could be made easily and cheaply by crushing scale insects.

However, there may also have been another factor in the demise of Tyrian purple. In 2003, scientists stumbled upon a pile of sea snail shells at the site of the ancient port of Andriake in southern Turkey. In all, they estimated that this garbage heap, dating to the 6th Century AD, contained around 300 cubic metres (10,594 cubic ft) of their remains – corresponding to up to 60 million individuals.

Intriguingly, though the bottom of the pile – where the snails were discarded first – contained some plump, older specimens, those discarded more recently were significantly smaller and younger. One explanation is that the sea snails had been overexploited and eventually, there just weren’t any mature snails left. This may have led to the extinction of dye production in the area, the researchers suggest.

But just a few years after this discovery, another would raise hopes of reviving this ancient colour.

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