To many people, asbestos will be forever associated with warning signs around old high school buildings, office towers, and dated apartment blocks. The fibrous, silicate material that has long been used as a fireproofing insulation has now also been known to be toxic. But as much as it may sound like a modern invention, asbestos has a long and eventful history and has been in use by human beings for more than 5,000 years.

Archaeological evidence shows that even in the Stone Age and early Bronze Age, around 3,000BCE, humans in northern Europe were using asbestos in firing pottery, and utilized its bizarre fibrous structure to strengthen clay pots and other vessels. The Ancient Egyptians wove asbestos fibers into their clothes to improve their durability and even used it in the mummification of some of their pharaohs and dignitaries. The Ancient Greeks likewise used asbestos in their clothing, as well as noting and studying its bizarre flame-retardant properties, while the name asbestos itself (which means “unquenchable”) was first given to it by the Roman historian and naturalist Pliny the Elder, as far back as in the 1st century CE.

The Romans too, opened asbestos mines all across the Mediterranean, and it’s often claimed that the workers in these mines—as well as their employers—were among the first people to note its toxicity to human health. (Reportedly, some Roman-era writers advised not buying or trading in slaves who had worked in asbestos mines, as they so quickly became ill.) The larger-scale mining of asbestos did not begin until much later, of course, and it was not until the 18th and 19th centuries that asbestos began to be produced industrially in any great quantity. It was even later—in fact, in the early 1900s—that the true extent of its negative effects on human health was finally described in any detail.

This extraordinary material has an equally extraordinary history. But perhaps the most bizarre chapter in this long history took place in the court of Charlemagne the Great, the first emperor of the Holy Roman Empire, more than a thousand years ago.

According to numerous contemporary accounts, Charlemagne—who ruled over Europe’s Holy Roman Empire from 800-814 CE—had a tablecloth woven from asbestos, with which to impress and amaze his dinner guests.

By Charlemagne’s time, the imperviousness and flame-retardant qualities of asbestos were well known: It is believed that some Christian pilgrims and clerics at the time would wear asbestos crosses, thinking their inflammableness proved they came from the true cross. For Charlemagne, however, these qualities were less of a chance to prove his religious devotion, and more a chance to wow his dinner guests.

Reportedly, Charlemagne would serve his guests a lavish banquet atop his asbestos tablecloth, and then once the plates, dishes, and goblets had all been cleared away, he would haul the cloth from the table and toss it into a fire in front of his presumably utterly bemused dining companions. The fire would burn off all the wine stains and spilled food from the surface of the cloth, of course, leaving only the unspoiled asbestos beneath it, utterly unharmed by the flames. The cloth could then be collected from the fire and thrown back over the table, ready to be used again.

Perhaps understandably, some of Charlemagne’s guests are believed to have become concerned that the emperor’s unburnable table cloth was the work of sorcery or black magic. Nowadays, of course, we know that it’s just another bizarre chapter in the equally bizarre history of this remarkable substance!