2,200‑Year‑Old Roman Shipwreck Reveals Ancient Naval Technology

Study Represents First-Known Evidence of Roman-Era Waterproofing

Working to determine how the ship was made waterproof, Charrié’s team produced the first known evidence of how Roman mariners maintained their vessels for long excursions. The primary waterproofing substance was pitch derived from heated conifer resin, but one sample contained an extremely rare mixture of pine tar and beeswax known as zopissa, which is described in ancient texts by Pliny the Elder. This blend offered a much greater flexibility and ease of application, demonstrating a sophisticated understanding of naval materials and technological exchange across the Mediterranean.

Pitch worked to trap microscopic pollen grains when applied to the wood surface. Charrié and her researchers used this method to reconstruct the vessel’s repair history via a palynological analysis. They found that the pollen was sourced from a wide variety of environments: Mediterranean coastal plants like olive and holly oak, wetland species such as alder, and mountain flora including fir and beech. This diversity indicates that the ship’s hull was coated in four to five separate repair episodes across different regions.

Earlier ballast-stone studies suggested that the boat was built near Brundisium, Italy, which is now modern-day Brindisi. The pollen data confirms this origin while subsequently revealing later repairs along the northeastern Adriatic, close to where the vessel ultimately met its demise. The findings paint a stunning, never-before-seen reconstruction of a Roman vessel’s operational life, demonstrating how ancient mariners routinely maintained their ships and how naval technologies evolved and spread across the Mediterranean. 

“These coatings bear witness to the ship's life over time and to its movements on the sea," Dr. Charrié said. "It highlights common patterns and regional specificities, notably in relation to the availability of natural resources. Finally, this research also demonstrates the evolution of practices and the transfer of technologies over time.”