In brief
Excavation teams at the medieval Rusokastro fortress uncovered a massive building whose thick stone walls and thick hydrophobic mortar layers point to a water reservoir or storage wing. The structure, positioned beside the inner southern fortress wall, yielded silver coins from Tsar Ivan Alexander’s reign and Venetian grosso coins, underscoring the site’s trading links during the 14th century. The find, part of state‑funded research, reaffirms Rusokastro’s strategic importance amid Bulgarian‑Byzantine conflicts.
During the latest season of excavations at the medieval town of Rusokastro, teams from the Regional History Museum of Burgas uncovered a monumental building measuring 7.60 metres across, whose walls, 1.1 metres thick, were constructed from stone bound with abundant mortar. The inner surfaces of the walls are coated in a thick, pink layer of hydrophobic – that is, water‑repellent – mortar. The combination of wall thickness and waterproof lining suggests the structure was used either as a water reservoir or as a storage wing for food supplies, a hypothesis that the archaeologists propose for the ground floor of a building that likely had a second, residential floor above.
Architectural Features and Functional Interpretation
The building’s location beside the inner southern fortress wall places it at the heart of the medieval urban core, a position often reserved for essential civic facilities. The 7.60‑metre width of the nave, coupled with the massive walls, indicate a design meant to accommodate a substantial volume of stored material, whether water or dry goods. The thick pink hydrophobic coating, unique to this structure and unknown in other Rusokastro buildings, points to a conscious effort to control moisture – either to keep water clean or to preserve the stored commodities from dampness and spoilage. While the exact function cannot be confirmed without further analysis, the architectural evidence favours a utilitarian role in the daily life of the town.
Artifacts and Material Culture
Inside the walls, workers recovered a wealth of artefacts that illuminate the town’s economic and political connectivity. Among them were silver coins minted during the reign of Bulgarian Tsar Ivan Alexander (1329–1371), alongside Venetian silver grosso coins known locally as “matapans.” The presence of copper coins, as well as various utilitarian objects, suggests a bustling trade hub capable of hosting both local and foreign currency. These finds are currently undergoing cleaning and conservation at the restoration laboratory of the Burgas Museum, ensuring their long‑term preservation and scholarly accessibility.
The catalogue of recovered items points to a sophisticated layer of economic exchange: reservoirs or storerooms in Rusokastro would have been essential for sustaining a fort with a sizeable garrison and civilian settlement, especially during sieges or periods of scarce supply. The mixture of Byzantine‑ruled, Bulgarian, and Venetian coins also hints at a cosmopolitan circulation of wealth, further underlining Rusokastro’s importance in the 14th‑century Black Sea trade network.
Historical Context and Strategic Significance
Rusokastro has long been recognised as a key strategic point on the Bulgarian border ridge of Erkesiya. In 1332, the fortress became the site of a decisive battle in which Tsar Ivan Alexander defeated the Byzantine army led by Emperor Andronicus, a conflict that is immortalised in chroniclers of the period. The fortress remained active until its destruction by Ottoman campaigns in 1443.
Historically, the name Rusokastro first appears in the Arabic geography of El Idrisi, who described the settlement as large and crowded. Byzantine chroniclers later mentioned the town, especially as the backdrop to the 14th‑century conflict. Today, Rusokastro is among Bulgaria’s priority archaeological sites, receiving state funding aimed at enhancing cultural tourism and preserving national heritage.
Funding and Research Collaboration
The excavation is funded by the Council of Ministers of the Republic of Bulgaria and Kameno Municipality, reflecting a joint commitment to uncovering and preserving the nation’s medieval heritage. The Regional History Museum of Burgas leads the project, conducting the research, documentation, and post‑excavation analysis.
With the monumental building’s discovery, scholars gain new insight into the civic infrastructure that supported not only military logistics but also civilian life in medieval Rusokastro. The integration of architectural evidence with the artefact assemblage renders a more nuanced picture of how the town functioned within the larger geopolitical and economic fabric of the 14th‑century Balkans. Further studies are expected to refine the building’s function, dating, and broader role in the fortress’s defensive and domestic systems.
