The Gravina Ravine as Building Site
Matera occupies the edge of a ravine — the Gravina di Matera — carved by a watercourse that has since retreated southward. The ravine walls are composed of calcarenite, a soft, fine-grained limestone that can be cut with metal tools but is strong enough to span small openings without additional support. These two properties — workability and compressive strength — made the ravine walls ideal for cave excavation.
The earliest occupation of the cave network is documented from the Neolithic period, with ceramics and lithic material recovered from lower levels of excavated grotticelle (small caves). By the early medieval period, the same spaces were being reused and extended as habitation units, and rupestrian churches began to appear from around the eighth century — many of them associated with the Byzantine monastic tradition that spread through southern Italy following the Lombard and Arab pressures on coastal settlements.
The two main districts, Sasso Caveoso to the south and Sasso Barisano to the north, face the ravine on opposite sides of the Piano hill (the Civita), on which the cathedral and historic centre stand. Each has a distinct character: Sasso Caveoso is steeper, with deeper caves and less constructed frontage; Sasso Barisano is more heavily built over, its cave origins masked by seventeenth- and eighteenth-century facades that give it a more conventionally urban appearance from the opposite bank.
Constructive Logic of the Cave Unit
The basic spatial unit of the Sassi is the vicinato — a cluster of cave openings, typically between three and twelve, that shared a single cistern, a communal terrace, and, often, a shared entrance sequence from the lane above. The arrangement was not merely social but hydraulic: every surface in the Sassi was designed to channel rainwater toward cisterns, and the cistern itself was the structural and economic core of each vicinato cluster.
The cave openings are almost always oriented toward the ravine — east or northeast — which in a temperate climate with hot summers and cold winters was a reasonable thermal strategy. The calcarenite maintains a relatively stable temperature throughout the year, and the depth of the cave (typically between three and eight metres for inhabited spaces) provided insulation from summer heat that the thin masonry frontages of contemporary built structures could not match.
Lighting was the primary constraint. Natural light reached only the front zone of each cave unit, typically a single room wide and open to the terrace or lane. Rear areas were permanently dark and served for storage, animal keeping (the stalla-grotta or cave stable), and winter sleeping. This separation of the lit and unlit zones within a single spatial unit is characteristic across the entire Sassi and distinguishes cave habitation from built-room habitation regardless of how elaborated the frontal masonry became.
Rupestrian Churches: Spatial Typology
The Sassi contain approximately 150 rupestrian churches, of which approximately 30 have surviving interior decoration. These range from very small single-nave spaces, barely large enough for a priest and two or three worshippers, to more elaborate multi-nave structures with carved pilasters, apses, and decorated capitals produced in imitation of contemporary built church forms.
The most extensively studied is the church of Madonna de Idris, cut into the flank of the Monterrone rock mass at the edge of Sasso Caveoso. Its interior retains Byzantine fresco cycles from multiple campaigns, the earliest identified as late eleventh century. The spatial organisation — a central nave flanked by lower side aisles — follows the three-aisle basilical plan but in negative: the nave is defined by the rock mass left standing between the side cuts rather than by columns inserted into a constructed space.
In rupestrian architecture, the wall and the column are the same material operation seen from different sides — one removes mass to create space, the other adds mass to define it.
The 1952 Evacuation and Its Consequences
In 1952, the Italian government under Prime Minister De Gasperi ordered the evacuation of the Sassi, declaring the cave dwellings incompatible with modern living standards. Approximately 15,000 residents were relocated to new apartment blocks on the plateau above. The Sassi remained largely empty for four decades.
The evacuation preserved the physical fabric in a way that continued habitation might not have — there were no incremental modifications for plumbing, electricity, and heating infrastructure of the kind that altered occupied vernacular buildings across Italy in the postwar period. When the Sassi were inscribed as a UNESCO World Heritage Site in 1993 and subsequently reopened for habitation and tourism, the fabric was essentially intact, requiring restoration rather than reconstruction.
The spatial consequences of tourism-oriented reuse are, however, significant. The vicinato clusters that functioned as semi-private communal spaces now operate as publicly accessible passageways. The cisterns, which were the hydraulic core of each cluster, are decorative features. The stalla-grotta units that formed the ground level of most vicinato complexes have become hotel rooms and restaurants. The functional logic that produced the spatial organisation has been replaced entirely, but the organisation itself survives — legible to analysis even as its original meaning has been evacuated.
Stone Quality and Construction Technique in the Built Frontages
Where the Sassi present built masonry rather than cut rock, the material is the same calcarenite — but now worked as cut blocks rather than extracted as negative space. The transition from rupestrian to masonry construction often happens within a single building, with lower walls built directly onto or against the ravine face and upper walls rising as constructed masonry above the natural rock line.
Seventeenth-century baroque façades in Sasso Barisano use the calcarenite for elaborate portal surrounds, console brackets, and window frames at a level of detail that demonstrates both the quality of the local stone and the skill levels available in a regional centre that, despite its poverty, maintained active craft traditions. The contrast between these decorated civic fronts and the rough extraction visible just behind them is one of the more arresting spatial experiences the Sassi offer.
