In brief
During the final phase of excavations at the medieval town of Rusokastro, archaeologists found a monumental building adjacent to the fortress’s inner southern wall. The 7.60‑metre wide structure, thick stone walls, and waterproof mortar suggest it may have served as a reservoir or food storage center. Artefacts including silver coins from Tsar Ivan Alexander’s reign and Venetian grosso coins are now undergoing conservation at the Burgas Museum.
Archaeologists working at the medieval town of Rusokastro on the Black Sea coast announced the discovery of a monumental building measuring 7.60 metres in width and 1.1 metres in wall thickness on 29 October 2026.
The structure lies immediately beside the inner southern fortress wall and was revealed during the final phase of a state‑funded excavation carried out by the Regional History Museum of Burgas.
Architectural evidence indicates that the building’s walls are constructed of stone bonded with an abundance of mortar and that the interior surfaces are coated with a thick layer of pink hydrophobic (waterproof) mortar. These features point to a practical function—either a water reservoir or a storage facility for food supplies—rather than a ceremonial or military building.
The team believes the uncovered section represents the ground floor of a multi‑storey complex. Archaeological models suggest an additional residential floor existed above it, possibly overlooking the town’s central quarter.
Alongside the architectural remains, a rich assemblage of artefacts was recovered. Chief among them are silver coins issued during the reign of Bulgarian Tsar Ivan Alexander, Venetian silver grosso coins known as matapans, copper coins, and other assorted objects. These items are currently undergoing cleaning and conservation at the restoration laboratory of the Burgas Museum.
Historical Context
The medieval town of Rusokastro is historically significant for its role in 14th‑century Bulgarian‑Byzantine conflicts. In 1332, under the leadership of Tsar Ivan Alexander, the fortress witnessed a decisive battle in which the Bulgarian forces triumphed over a Byzantine army commanded by Emperor Andronicus, a victory recorded by chroniclers of the era.
The importance of the fortress was such that it was first mentioned by the Arab geographer El Idrisi in his work “Geography of the World”. He described Rusokastro as a large and populous town, a characterization echoed by Byzantine chroniclers in their accounts of 14th‑century events.
The fortress endured destruction during the Ottoman campaigns of 1443, and since then it has been one of the largest forts protecting the Bulgarian border ridge known as Erkesiya during the 10th‑11th centuries.
Because of its historical value, Rusokastro has been included in the national heritage register and receives priority state funding to support cultural tourism development.
The current excavation is fully financed by the Council of Ministers of the Republic of Bulgaria and Kameno Municipality, reflecting the continued investment in uncovering the site’s past.
With the discovery of a building that appears to have been a central component of the medieval town’s infrastructure, the excavation team is now turning its attention to a wider sweep of the site. Further investigations may reveal additional floors, extensions, or related structures that could paint a more comprehensive picture of life in Rusokastro during the 14th century.
Open questions remain regarding the exact length of the building, the precise nature of the artifacts recovered, and the relationship of this structure to other parts of the fortress. The conservation team at the Burgas Museum will continue to prepare the items for public display, adding to the legacy of Rusokastro as a key chapter in Bulgaria’s medieval history.
