It's always a risk to take your valuables into a swimming pool. The Romans should have paid better attention, judging by the amount of gemstones recovered from the drain of one of their bathhouses.
As many as 30 semi-precious stones have been discovered by archaeologists nearly 2,000 years after their owners lost them at a site in modern-day Carlisle, just behind Hadrian's Wall.
The stones had dropped out of their ring settings, their glue probably weakened in the steamy baths. When the pools and saunas were cleaned, they were flushed into the drains.
Their loss would have been painful as these were engraved gems, known as intaglios. They are barely a few millimetres in diameter, but they bear images whose extraordinary craftsmanship suggests they would have been expensive items in their day the late 2 nd century or 3rd century.
One bather lost an amethyst depicting Venus, holding either a flower or a mirror. Another had a red-brown jasper with a satyr sitting on rocks next to a sacred column.
Frank Giecco, an expert on Roman Britain who is running the bathhouse excavations, was amazed by the collection: It is incredible, he said. It caught everyone's imagination. They were just falling out of people's rings who were using the baths. They were set with a vegetable glue and fell out of the ring settings in the hot and sweaty bathhouse. He can imagine the Romans cursing after realising their loss. They may not have noticed until they got home, because it is the actual stone falling out of the rings, although we have also found a ring with a setting. Professor Martin Henig, an expert on Roman art at the University of Oxford, said metal expands. If the stone is not secured properly, it can fall out, as it can with people bathing. I imagine that the gems recovered from the drain were accumulated over time, and we must remember that a lot of people used those baths. There were previously recovered intaglios from drains in York and Caerleon near Newport. The Romans faced a dilemma that they still face today, of losing their valuables in the water or to a sneak thief while they were bathing. This is reflected in several curse tablets found in Bath and elsewhere, which wished revenge on the perpetrators of such crimes.
One of the curses targets a ring thief: so long as someone, whether slave or free, keeps silent or knows anything about it, he may be accursed in blood and eyes and eyes and even have all intestines quite eaten away if he has stolen the ring. Henig said that there were dangers, but the difficulty was that you had to take your ring off. People were very upset when they lost a ring or the gem set in its bezel. The bathhouse was adjacent to the most important Roman fort on Hadrian's Wall, the northern frontier, which held an elite cavalry unit and had links to the imperial court. Excavations will continue next year, but the evidence recovered so far, including imperial-stamped tiles, shows that the bathhouse complex was monumental and opulent.
Giecco said: You don't find such gems on low-status Roman sites. They are not something that would have been worn by the poor. As rings worn by men and women, there was a symbolism within their imagery. The newly discovered intaglios include military themes such as the god Mars holding a spear, and fertility, notably a charming image of a mouse nibbling a branch Romans saw mice as symbols of rebirth or fertility.
Giecco said: Some of the intaglios are minuscule, around 5 mm 16 mm is the largest intaglio. The craftsmanship to engrave such tiny things is incredible. The drain discoveries also include more than 40 women's hairpins and 35 glass beads, probably from a necklace.