Secret of Alexander the Great Pompeii Mosaic Revealed

An international and interdisciplinary team of scientists has published in the journal PLOS ONE the results of a survey of the mosaic, housed in the National Archaeological Museum of Naples, Italy.

As Phys.org reports , the researchers used handheld X-ray fluorescence to identify chemical elements in the rocks that make up the mosaic.

The last one was found in 1831 in the House of the Faun in Pompeii. It depicts a real historical episode – the battle between the troops of Alexander the Great and the Persian king Darius III, which took place in 333 BC near the Pinarus River, on the border of modern Turkey and Syria.

The brutal battle pitted 75,000 Greeks against about 600,000 Persian soldiers. This event went down in history as the Battle of Issus. Despite the Persians' enormous numerical superiority, the battle ended in a decisive victory for Alexander the Great. Darius III was forced to retreat deep into his empire, and the Greeks occupied Syria and Phoenicia.

In the new study, scientists used non-destructive analytical methods to avoid damaging the valuable mosaic and to assess its current state of preservation.

In addition, analysis of the building materials allowed us to understand how the mosaic was created. For example, X-ray fluorescence showed that the image of Alexander the Great's face was composite. It was made up of pink tesserae, presumably imported from what is now Portugal, with wax and plaster applied as a protective layer.

However, there is an assumption that the protective layer appeared not during the creation of the mosaic, but much later, during restoration work or, perhaps, before the transportation of the mosaic from the city of Pompeii to the Naples Museum in 1843.

The analysis showed that not all of the mosaic is covered with a protective layer of gypsum and wax. However, it is possible that it existed, but has simply worn off by our time. As part of the planned restoration work on the artifact, a new protective layer is expected to be applied.

The study also confirmed that the mosaic was created by the Romans about 200 years after the Battle of Issus, specifically for the floor of the House of the Faun in Pompeii. The author probably wanted to immortalize an important historical event.

Interestingly, scholars call the Roman mosaic just a copy. It is believed that the original was created around 300 BC by the Greek master Philoxenus of Eretria.

The mosaic, measuring 5.82 x 3.13 metres, consists of more than 1.9 million individual tiles. It is a highly detailed image. Multispectral imaging has made it possible to separate the fragments of material into four main groups. It has been established, for example, that the tiles in white, red, yellow, green and light blue came from Italian and Mediterranean quarries.