Using a non-invasive method of analysis, researchers have discovered that the pieces making up the famous Pompeii mosaic of Alexander the Great came from a network of quarries across Europe.
Alexander the Great is remembered today for his military conquests and empire-expanding activities (and perhaps for being the main character in that 2004 movie with terrible accents). Born in 356 BCE, he was a ruler of the ancient Greek kingdom of Macedonia, located in the northeastern corner of the Greek peninsula. Although he only ruled for 13 years, his military genius enabled him to establish an empire that spread the influence of Greek culture (Hellenism) from his homeland to Egypt and from Greece to parts of India.
He has long been recognized as a superb military general, but he died due to unknown causes at the age of 32. Ever since, his name has gone down in history as one of the, well, greats. His story has inspired various artistic representations over the centuries, especially among the Romans, as well as stories and myths that became popular in the medieval period.
The most iconic and impressive example of the former is the Alexander Mosaic, which was created around 2,000 years ago in the Roman city of Pompeii. This artwork depicts Alexander on horseback, along with his Macedonian army, as they defeated the Persian army led by Darius III, King of Persia, in the Battle of Issus (333 BCE).
Fun fact: Arab sources and other texts from the medieval period, including the book of Marco Polo, recall the Battle of Issus as the “battle of the dry tree” or “the solitary tree”, which is regarded as a precise reference to the only landmark in the image: a lone tree.
The mosaic is made up of millions of tiny tesserae – small, regular pieces of hard material used in mosaics – that cover an area measuring 583 by 325 centimeters (230 by 128 inches).
It’s an incredibly detailed piece of art, but it was lost to history when Mount Vesuvius erupted in 79 CE. The mosaic was then rediscovered in 1831, when archaeologists discovered what they called the House of the Faun, which belonged to a wealthy family. The mosaic is now housed at the National Archaeological Museum of Naples.
In 2020, the museum launched a restoration project that included the first-ever diagnostic assessment of its pieces using non-invasive imaging and spectroscopic techniques. The team also employed portable X-ray fluorescence (pXRF) to identify specific elements within the piece. The results were impressive.
“The so obtained data allowed to depict the chemical and mineralogical composition of the tesserae used for the manufacturing of the Mosaic, along with a tentative hypothesis on the provenance of the natural ones”, the team writes in the study describing their findings.
They found that the tesserae were composed of ten types of colors – white, brown, red, yellow, pink, green, grey, blue, black, and glassy (vitreous) – that were arranged to produce the image. The pieces also had a range of micro-textures that were “masterfully combined to enhance artistic effects of the artworks”.
Induced luminescence imaging revealed that Alexander’s face alone was made up of several shades of pink tesserae with different luminescence, giving the flesh a more realistic appearance.
The tesserae themselves came from quarries that were used by the Romans at the time. Some of the white pieces may have come from the Apuan Alps quarries in Italy, which the Romans started to mine for marble in the 1st century BCE. The pink pieces likely come from sites in Portugal, while some of the yellow tesserae may have come from the Roman city of Simitthus in Tunisia. In addition, the light red pieces may have come from the Apuan Alps or from Sicily, and the dark red tesserae possibly from Cape Matapan in Greece.
Traces of wax, mineral gypsum, and calcium oxalate were also found. These substances were probably applied to the mosaic during earlier restoration efforts; calcium oxalate may have been a by-product of organic protective coatings, while the gypsum, which is widespread throughout the mosaic, probably came from protective layers added to the piece when it was transported to the museum in the 19th century.
The mosaic is now undergoing restoration, and new data on the underlying mortars have been gathered by researchers. The team of this current study concludes that “the combination of these new data, along with information obtained from a new instrumental investigation campaign planned for the mosaic surface in the final phases of the restoration operations, will further enrich our knowledge of this superlative work of ancient art.”
The study is published in PLoS ONE.
