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  • Researchers identified conifer pitch and beeswax mixtures on a Roman shipwreck, suggesting the use of traditional Greek waterproofing techniques.
  • Pollen trapped in the coating provides evidence of the vessel's construction site in Italy and subsequent repairs along the Adriatic coast.
  • The study highlights how organic materials serve as critical records of ancient naval technology and maritime trade networks.

A Roman Republic-era shipwreck discovered off the coast of Croatia has yielded new evidence regarding how ancient sailors maintained their vessels. The wreck, known as Ilovik–Paržine 1, sank in the Adriatic Sea during the second century B.C.E. while carrying timber and wine. Recent analysis of the hull’s protective coating reveals that the ship was treated with organic materials designed to shield the wood from seawater corrosion.

The study, published in Frontiers in Materials, examined ten samples taken from the vessel's exterior. The primary component identified was pitch derived from conifer trees, specifically from the Pinaceae family. This substance would have been heated and applied to create a barrier against water intrusion. The presence of these materials underscores the importance of organic waterproofing in ancient shipbuilding, an area that archaeologists note has historically received less attention than structural elements.

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One sample presented a more complex composition, containing a mixture of tar and beeswax. This formulation is known from ancient texts as zopissa, a term used by Pliny the Elder to describe pitch macerated with saltwater and wax. Adding beeswax likely increased the flexibility of the coating, making it easier to apply and maintain. The use of this specific mixture on a Roman vessel suggests a continuity of technical knowledge from earlier Greek shipbuilding traditions.

The researchers argue that the presence of zopissa on a Roman ship reflects the transfer of technology across the Mediterranean basin. Rather than developing entirely new methods, Roman builders may have adopted established practices from neighboring cultures. This finding challenges the notion that ancient maritime technologies were static or isolated, instead pointing to a dynamic exchange of skills and materials among seafaring communities.

Beyond chemical composition, the coating provided clues about the ship's geographic history. Sticky pitch tends to trap airborne pollen, preserving microscopic plant grains within the material. By analyzing these pollen samples, scientists could identify the types of vegetation present when the coating was applied. The dominant pollen species included holm oak, pine, olive, alder, ash, and hazel.

These plant species are characteristic of Mediterranean and Adriatic coastal environments. Their presence aligns with previous geological analysis of the ship's ballast, which suggested the vessel was constructed near Brindisi on Italy’s southeastern coast. The pollen evidence supports the theory that the initial waterproofing layer was applied in this region before the ship embarked on its final voyage.

Statistical analysis of the samples revealed four to five distinct batches of coating material. This variation suggests that the hull underwent multiple applications or repairs over time. Some samples contained small amounts of fir and beech pollen, which are associated with mountainous regions in the northeastern Adriatic, including areas near Istria and Dalmatia.

The presence of these northern pollen types indicates that maintenance work was likely performed closer to the ship's sinking site. This finding provides rare physical evidence of how ancient ships were serviced during long-distance travel. It demonstrates that vessels were not only built in specific locations but also repaired using locally available materials as they moved through different maritime zones.

The study emphasizes the value of organic residues in archaeological research. While wooden hulls often decay, the chemical signatures of protective coatings can survive for millennia. These materials offer a detailed record of naval technologies that would otherwise be lost. By examining such traces, researchers can reconstruct navigation routes and understand the practical challenges faced by ancient mariners.

Future analysis may further clarify the extent of technological exchange in the ancient Mediterranean. The Ilovik–Paržine 1 wreck serves as a case study for how material science can illuminate historical practices. As more shipwrecks are studied using similar methods, our understanding of ancient maritime economies and engineering capabilities is likely to deepen.

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  • Smithsonian Magazine↗A Brittle Coating on a 2,200-Year-Old Roman Shipwreck Reveals How Ancient Sailors Kept Their Ships Afloat