The Tauchira Gate at Ptolemais in 2006: view from the west. Photograph by Miron Bogacki.

Archaeologist Finally Decodes 2,200-Year-Old Mysterious Stonemason Inscriptions That Have Stumped Researchers for Centuries

A University of Warsaw scientist has determined that a series of mysterious stonemason inscriptions on the Tauchira Gate at Ptolemais, on Libya’s northern coast, which have perplexed researchers for centuries, are likely stonemason marks intentionally left visible by the artisans who built the ancient structure.

The new analysis, which was performed by Anna Urszula Kordas of the Faculty of Culture and Arts at the University of Warsaw in Poland, also dates the gate’s construction to the reign of Ptolemy VIII, roughly 2,200 years ago.

If correct, the new dates for the site would help settle a longstanding debate about the gate’s precise age.

Mysterious Stonemason Inscriptions Regularly Misidentified

According to Korda’s research study, archaeologists consider the Tauchira Gate to be the best-preserved section of the ancient fortifications built around the ancient Egyptian city of Ptolemais. Several visitors and scholars have noted the gate over the centuries, with a particular focus on its mysterious stonemason inscriptions.

The earliest documented attempt by a Western researcher to decipher their meaning comes from a French traveler identified as Granger, who recorded the marks sometime between 1733 and 1734. According to Korda, that first attempt mistakenly described the marks as likely instructions for masons to arrange the gate’s stones during its construction.

mysterious stonemason inscriptions
The north wall of the Tauchira Gate bears mysterious stonemason marks. Image Credit: Miron Bogacki, University of Warsaw/European Journal of Archaeology, © Kordas, A.U. 2026. Published by Cambridge University Press on behalf of The European Association of Archaeologists.

A second, 19th-century effort inaccurately ascribed the mysterious stonemason inscriptions to donors financing specific blocks. In the 1970’s, another researcher suggested the inscriptions were ‘ephebic’ names added after construction as graffiti “unrelated to the gate’s construction but connected to the functioning of the nearby gymnasium.”

Although the most recent effort dated the inscriptions to sometime during the city’s Roman period, Korda notes that the date is still in debate. She also points out that the meanings of the mysterious stone inscriptions were unlikely to be any of the proposed explanations, motivating the new analysis.

2006 Photos Enable Digital Recreation and Discovery of Techniques

To decipher the mysterious stone inscriptions, Korda said she reconstructed the gate’s construction process, organization, and chronology by applying the “chaîne opératoire approach.” This method allowed Korda to study these variables “within its technological and socio-cultural context.”

Thanks to a series of photographs captured by the Polish Archaeological Mission to Ptolemais in 2006, Korda was able to trace the location of each inscription using digital mapping software. The researcher notes that this process still included challenges, including “damaged stone surfaces, suboptimal picture quality, invasive plants, and later inscriptions,” all of which made some of the actual stone markings illegible. Korda said these limitations also hampered the “observation of stone processing techniques.”

mysterious stone inscriptions
Above: A view of the Tauchira Gate from the eastern side of the town (Image Credit: Photographs by Miron Bogacki). 

After a thorough initial examination, Korda separated the mysterious stonemason inscriptions into 27 ‘types’ and then split them into two groups. The first group represented marks found on rough, unfinished blocks. These marks were also mostly hidden from view, suggesting they were recorded during a block’s quarrying and transport.

Korda’s second group included inscriptions found on finished, textured outer surfaces of the gate’s two towers. Notably, the second group of markings appeared to be carved with more care than those in the first group.

Mysterious Stonemason Inscriptions Likely Stonemason Marks Identifying Workers and Work

Korda ultimately determined that the inscription pattern represented two distinct systems used to organize and pay for stonemason work. For example, some marks appear to follow a simple letter sequence, which Korda suggests shows how the team was divided for work.

“The stonemasons’ marks on the Tauchira Gate consist of single Greek letters, double letters, ligatures, and elaborate monograms,” the study author writes. “The marks A, Β, Γ, Δ, AP/Ε, Ζ, and Η likely form a letter-label system representing the division of labour among stonemasons’ teams.”

The analysis also revealed some of the mysterious stone inscriptions combine to form complex monograms. Korda said these inscriptions “appear as ligatures or monograms, possibly abbreviating stonemasons’ names.” The inscriptions also likely represent names or workshop owners or private donors who helped fund the project, a common Greek practice during this era.

“The hypothesis presented here is that the marks, especially attested in the lower levels, correspond to the division of stonemasons into seven teams numbered A to H and suggest a well-organized system, possibly financed from public funds,” Korda writes.

mysterious stone inscriptions
Didyma, Temple of Apollo: stonemasons’ marks on unprocessed stone blocks visible on the southern inner wall of the temple, along with smoothed blocks without marks (Image Credit: Photographs by Miron Bogacki).

One unusual aspect highlighted by Korda’s work was that the mysterious stonemason inscriptions were not hidden during construction, unlike stonemason marks found at other ancient construction sites. The researcher suggests that the marks on the Tauchira Gate being left visible were an intentional act representing a local tradition instead of a wider societal practice.

“Even in the absence of instructive parallels—whether due to lost evidence or gaps in research—it may be inferred that the practice of inscribing rusticated blocks with masons’ or patrons’ names, while inspired by the broader Greek tradition of commemorating benefactors on public buildings, represents a local innovation,” Korda writes, adding that the Tauchira Gate is, therefore, “remarkable for its distinctiveness, as fortifications displaying comparable evidence for labour organization and the public display of stonemasons’ marks remain without close parallels.”

Analysis Includes Early Second Century Construction Date

Along with successfully deciphering the meaning of the mysterious stone inscriptions, Korda’s analysis determined that the gate’s two towers were built at the same time instead of one after another. Kordas said this finding contradicts a 2009 German team that examined the site in person.

Because the gates lack organic material for radiocarbon testing, Kordas dated their construction by comparing the shapes of the letters used in the inscriptions with other inscriptions from the same region that have been conclusively dated. The researcher also factored in nearby graffiti mentioning a visitor from Rhodes, which helped narrow the site to the earlier half of the second century BC.

“The arguments deployed by the epigraphic analysis of the marks on the Tauchira Gate and the evidence of the stonemasons’ marks visible there and presented in the analysis submitted here suggest that the gate was remodeled during the reign of Ptolemy VIII Physcon in the second century BC,” Korda concludes, adding that “at the very least, the hypothesis merits serious consideration.”

The article “Life on a Hellenistic Construction Site: Stonemasons’ Marks on the Tauchira Gate at Ptolemais in Cyrenaica” was published by Cambridge University Press.

Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org