São Pedro do Sul Roman Baths by João Mendes Ribeiro

Located on the banks of the Vouga River in São Pedro do Sul, Portugal, the São Pedro do Sul Roman Baths stand as one of the country’s most significant archaeological and architectural heritage sites. Originally constructed in the 1st century AD, the Roman Baths complex has remarkably preserved much of its original structure, leading to its classification as a National Monument in 1938. The restoration project by João Mendes Ribeiro, completed in 2019, carefully balances archaeological conservation with contemporary architectural intervention, ensuring the site’s historical integrity while enhancing its spatial legibility and public use.

Over centuries of continuous occupation, the Roman Baths accumulated subtle transformations without compromising the essence of the original Roman construction. Large portions of the Roman masonry walls remain intact, and traces of the original vaults are still clearly visible. Rather than reconstructing the building in a literal or speculative manner, the architectural approach focused on minimal intervention, guided by a deep respect for the ruin as both a historical document and a spatial experience. The project sought to recover the defining qualities of Roman bath architecture: scale, light, and the presence of water, allowing visitors to perceive the site as an immersive, sensory environment rather than a static ruin.

The complex is organized into two primary volumes, each addressed with a distinct conservation strategy. In the east volume, the intervention aimed to recover the original dimensions, construction techniques, and traditional materials. Collapsed walls were carefully rebuilt, restoring the geometry of the façade and re-establishing the rhythm of windows and solid masonry. This reconstruction reinforces the spatial clarity of the baths while maintaining continuity with the original Roman fabric.

In contrast, the west volume, also of Roman origin, was intentionally preserved as a ruin. Here, the architectural language emphasizes archaeological authenticity. The original height of the space was reinstated to suggest the scale of the Roman interior, while a new brick vault was introduced, precisely following the traces left on the original end wall. Importantly, this new vault does not impose structural loads on the Roman walls; instead, it is suspended from the roof structure, ensuring full protection of the historic remains. Overhead natural light enters through a south-facing lantern, recreating the luminous atmosphere typical of Roman bath spaces and reinforcing the connection between architecture and climate.

The surrounding exterior areas were treated with equal care. Key elements such as the cold water tank and the natatio swimming pool were restored, with the latter resurfaced in opus signinum, a traditional Roman waterproof mortar. The reconstruction of the east volume was deliberately designed to avoid contact with the original edge of the natatio, preserving the archaeological boundaries and ensuring reversibility.

Archaeological research conducted by Helena Frade revealed evidence of a peristyle surrounding the exterior natatio. This discovery led to a collaborative intervention with landscape architect João Gomes da Silva, who developed a peristyle reconstruction using fragments of original Roman columns found scattered across the site. Through the process of anastylosis, existing elements were reassembled and complemented with new components, carefully proportioned according to Vignola’s Treatise of Architecture. In accordance with the Athens Charter, the distinction between original and new elements remains clearly legible, reinforcing the project’s ethical approach to heritage conservation. A new external wall was also introduced to emphasize the site’s entrance and improve spatial orientation.

Water plays a central role in both the historical function and contemporary interpretation of the baths. The restoration reinstated the original water intake and distribution system, allowing water to flow throughout the complex as a continuous circuit. Interior pools, the exterior cold water tank, and the natatio are all reactivated, transforming water into a narrative device that guides movement, signals transitions, and enhances sensory perception. Through sound, reflection, and movement, water reconnects the architecture to its Roman origins while offering a renewed, experiential reading of the space.

All photographs are works of Alexander Bogorodskiy