For over two millennia, humanity’s intimate relationship with the sea has necessitated formidable shipbuilding technologies, particularly the creation of durable, waterproof vessels capable of enduring the harsh influence of saltwater and marine organisms. Despite this, historical studies have largely overlooked the non-wood materials used in ancient ship construction, especially those designed to waterproof and protect hulls. Now, a pioneering international team has embarked on a groundbreaking analysis of the adhesive coatings employed on a Roman Republican shipwreck, illuminating forgotten naval technologies that have guarded seafaring craft since antiquity.
Excavated off the Croatian coast near the island of Ilovik, the Ilovik–Paržine 1 shipwreck sank approximately 2,200 years ago. While the hull and its cargo of logs and amphoras have been studied, the complex organic materials used for its waterproof coatings remained a mystery until now. Employing a combination of advanced molecular and palynological (pollen) analyses, researchers from France and Croatia have unveiled the composition and provenance of the ship’s adhesive layers. This work critically bridges archaeology, chemistry, and botany, offering unprecedented insights into ancient maritime craftsmanship.
Organic coatings, often disregarded in classical archaeology, are essential for vessel longevity and performance. Dr. Armelle Charrié, an archaeometrist from Strasbourg’s Laboratory of Mass Spectrometry of Interactions and Systems, emphasized that these organic materials are “true witnesses of past naval technologies.” The team identified two distinct coatings on Ilovik–Paržine 1: a pine tar (or pitch) based adhesive and a composite blend of pine tar and beeswax. Notably, pollen trapped within these substances acts as a botanical fingerprint, revealing the vegetation present during the coatings’ preparation and application, and thus offering clues to the environmental context of the ship’s maintenance.
The discovery of pine tar coatings corroborates its known use as a natural sealant in antiquity. Pine tar, derived from heated conifer resin, provides a viscous, water-resistant barrier critical to protecting wooden structures from marine biofouling and structural decay. Analyzing ten distinct coating samples via mass spectrometry allowed for precise molecular fingerprinting. One of these samples contained a mixture combining pine tar with beeswax known historically to Greek shipbuilders as zopissa. This blend enhances flexibility and adhesiveness, facilitating the application of the waterproof layer, especially when heated, demonstrating sophisticated ancient material engineering.
A particularly compelling aspect is pollen’s role as a time capsule embedded within the coating layers. As pitch is inherently sticky, it captures pollen grains from the surrounding environment. Analyzing the diversity and concentration of these microscale plant remnants revealed a specific biogeographical signature. The pollen assemblage featured flora characteristic of the Mediterranean and Adriatic coastal mosaic: holly oak, pine forests, Mediterranean shrubland known as matorral, and Mediterranean tree species such as olive and hazel. The presence of alder and ash denotes riparian vegetation found near sea and river margins, while fir and beech pollen hints at upland mountain sources.
The palynological data suggest that the pine tar or pitch was sourced from multiple regional forest types, pointing to the procurement of materials from varied ecological zones along the Adriatic. The pollen signatures align with the coastal and mountainous geography of northeastern Adriatic territories like Istria and Dalmatia, matching the shipwreck’s modern discovery site. This multiregional origin supports the hypothesis of the vessel receiving periodic refurbishments during its operational lifespan, utilizing locally available natural resources for coating repairs.
Molecular analyses uncovered at least four to five distinct episodes of coating application on the vessel, reinforcing the idea of recurrent maintenance. Interestingly, coating compositions on the ship’s stern and central hull were similar, while multiple, chemically and botanically distinct layers appeared on the bow. This stratification implies that as the ship aged and undertook long voyages, it underwent sequential patching, possibly reflecting stopovers in different Mediterranean ports where repairs were needed, and materials were variably sourced.
Additionally, this multimethodological study complements prior research on ballast stones from the Ilovik–Paržine 1, which identified Brundisium (modern-day Brindisi) on Italy’s southeastern coast as the probable original shipbuilding site. The pollen profiles from some coatings causally link the pitch to this region, while others suggest later interventions occurred closer to the Adriatic coast where the ship ultimately met its fate. This evidentiary chain elegantly ties together shipbuilding provenance, maintenance patterns, and regional maritime networks during the Roman Republic era.
From a technological perspective, the identification of zopissa—a beeswax and pine tar mixture—is especially illuminating. Its enhanced adhesive properties imply a sophisticated understanding of composite materials by ancient Mediterranean shipwrights. This knowledge optimized hull protection and maintenance, significantly extending a ship’s service life. The unique chemical signatures identified through mass spectrometry affirm that such coatings were not mere random applications but deliberate techniques embedded in maritime tradition.
This research not only fills a critical gap in underwater archaeology but also broadens our appreciation of the complexity inherent in ancient shipbuilding materials. Studies like this highlight how integrating molecular chemistry and palynology can extract nuanced historical narratives from otherwise overlooked organic residues. The dialogue between preserved biomolecules and trapped pollen offers a compelling reconstruction of past human-environment interactions and technological ingenuity.
Such investigations bear strong implications for both archaeological methodology and conservation science. Understanding the chemical nature and sources of these coatings informs artifact preservation strategies, ensuring that future underwater excavations encompass a broader analytical scope. More broadly, the work underscores how refined scientific approaches can revive ancient knowledge systems, illuminating the meticulous craftsmanship that sustained Mediterranean maritime culture for centuries.
In conclusion, Dr. Charrié and colleagues’ molecular and palynological analysis of the Ilovik–Paržine 1’s protective coatings reveals a vibrant narrative of shipbuilding mastery, material innovation, and environmental connectivity during the Roman Republic. Through identifying ancient composite sealants and their botanical provenance, the study offers not only a window into historical ship repair practices but also a transformative model for exploring organic archaeological materials that shape our understanding of maritime history.
Subject of Research: Not applicable
Article Title: Adhesive coatings in naval archaeology: molecular and palynological investigations on materials from the Roman Republican wreck Ilovik–Paržine 1 (Croatia)
News Publication Date: 24-Apr-2026
Web References:
http://dx.doi.org/10.3389/fmats.2026.1758862
Image Credits: Adriboats © L. Damelet, CNRS/CCJ
Keywords: Roman shipwreck, pine tar, pitch, beeswax, zopissa, molecular analysis, pollen analysis, naval archaeology, Adriatic, composite adhesives, maritime technology, ancient shipbuilding
